static site checker


known issues
bug reporting
boot notes
copyright & licence


The static site checker is an opinionated HTML nitpicker, a command–line tool to validate static HTML & XHTML websites. I built it to nitpick arts & ego, my hand–coded identity website.

It should not be used on untrusted content; its parsers are holier than Robin’s cow.

If you want to try it, play with the form below, or, if you’re really enthusiastic, here’s the current source.

Dylan Harris
September 2023

why SSC

Why did I make the static site checker? Aren’t there a lot of other HTML validators around? When I checked a few years ago; I couldn’t find a web site validator, only web page validators. Things may have improved. Anyway, my google fu is poo.

My identity website has more than 100,000 pages. I’m too impatient to push each through a validator one by one; I want to validate my site as a whole. Furthermore, single page validators can’t catch inter–page errors, such as broken internal links, let alone hidden links (an otherwise valid link to a HIDDEN element).

Many people avoid such problems by using frameworks. I find frameworks awful. IMAO, they produce dull, boring, trite design. The visual arts world has had centuries to develop excellent form for a rectangular space. Most 21st frameworks are so crude they haven’t even absorbed 14th century visual arts’ ideas, when painters broke out of rectangular form in a rectangular frame. So much is possible, so much hasn’t happened. I want to break this dull, stultifying, archaic, mutton.

Maybe I’m making the wrong comparison, that the web isn’t about image, it’s about type. The Western visual arts never did really suss mixing writing and form (that’s not really true, but, IMAO, such arts never escaped their context). However, the Eastern visual arts most certainly did, and frameworks haven’t noticed them either.

Enough of this. Rather than criticising other people for not doing, I should do. I need to make some example sites. That’s where SSC comes in.

If I am to build a site using an experimental visual process, I can’t use frameworks. If I can’t use frameworks, I have to hand code. And there’s the key problem: HTML is such a convoluted, evolved mess, that the people who designed it, in their own design presentations, make errors. Ok, I only found this out by testing SSC on them, which conveniently illustrates that HTML is overcomplicated. I’m not going to reveal names because these people are working hard to make the web a better place. Let’s just say W3 had broken links, WhatWG referenced withdrawn ontologies, and many other authors’ sites have other internal inconsistencies. That the people who define the web make mistakes using their own design in their own documents that espouse their design, helps explain why most stick to dull, formulaic, boring, frameworks. To be fair, my HTML is far worse than any of these mild examples of technical naughtiness, which is why I had to write SSC.

I’ve yet to build a site inspired by visual art’s form and layout. My efforts have been spent building SSC, a tool to make that practical.

Since I’m here, I’ll list other issues I have with frameworks:

Dylan Harris
October 2022


Static Site Checker
(an opinionated HTML nitpicker)
version 0.1.35
(c) 2020-2023 dylan harris
see LICENCE.txt & LICENSE.txt for copyright & licence notice

ssc analyses static HTML snippets, files and sites:
— HTML living standard, Jan 2005 to Jul 2023
— HTML 1.0/+/2.0/3.0/3.2/4.00/4.01/5.0/5.1/5.2/5.3–draft
— CSS 1/2.0/2.1/2.2–draft Feb 2022, some 3/4/5/6
— SVG 1.0/1.1/1.2 Tiny/1.2 Full/2.0/2.x–draft Apr 2021
— MathML 1/2/3/4–draft Jul 2022
— XHTML 1.0/1.1/2.0/5.x
— finds broken links
— server side includes, mostly
— many microdata & RDFa ontologies, including
— from 0.10 to 22.0

with opinions on:
— standard english where dialect is required
— perfectly legal but sloppy HTML
— abhorrent rudeness such as autoplay on videos

It does NOT:
— analyse or understand scripts
— analyse or understand XML or derivatives, except as noted above

It can output:
— ‘repaired’ HTML (not XHTML)
— HTML with resolved server side includes
— JSON of ontological content
— website statistical information
— deduplicated websites

ssc -h
for a usage summary.

ssc -f config_file
analyse site using preprepared configuration

ssc directory
analyse website based in directory

To build & run:
1. Follow the build instructions in build.txt
2. Gleefully run ssc. It will misbehave if you are insufficiently gleeful.

This is an alpha version of ssc. It may contain unexpected features.
If you encounter such a delight, please help improve ssc by collecting
the following information (where relevant):
— version of ssc;
— precise version of the operating system;
— hardware architecture and system information;
— detailed description of the problem;
— detailed description of the steps to recreate it;
— copy of output file showing the error;
— copy of pages/website being analysed;
— precise command used;
— configuration file(s) used, if any;
— any ndx file or other pre–existing file used during the run;
— any known workarounds or solutions;
— optionally, a dance interpretation of the ‘feature’;
and emailing everything to (if the collected files are more
than small, please use a public fileserver and email the link). Do NOT
send anything confidential. Furthermore, unless you state otherwise,
we reserve the right to publish some or all of the information sent in
future versions of ssc, usually in the test suite. If you have a fix,
you are invited to submit a pull request on github. Thank you.

SSC can be run in a CGI environment. This is intended for use with OpenBSD’s native httpd web server.
You are reminded that SSC is α software. Do NOT expose it to untrusted data
sources, such as the open web, without taking serious precautions. SSC probably has
more bugs than the Creator’s Ultimate All–Beetle Extravaganza (J.B.S.
Haldane, apocryphal : “[the Creator has] an inordinate fondness for beetles.”).

Notes on names:
— recipe: a nod to Vernor Vinge’s “A Fire Upon the Deep”;
— tea: without tea, nothing works; then there’s builders’ tea;
— sauce: makes the dull tasty; identifies incompetent pedants;
— toast: toasts code; i liked burnt toast;
— heater: i’m not stopping now;
— unii: my preferred plural of unix: to my ears, both unixes and unices
        sound like they sing castrato.
— andor: and/or sans ancienne; land of Gift (aber nicht das Gift)

build.txt        notes on building ssc
gen.txt          a model man page
usage.txt        how to use ssc
releasenotes.txt chips
LICENCE.txt      ssc licence information
LICENSE.txt      formal GPL 3 licence
more licences    licences for borrowed external content

I have a website, arts & ego, at It has
approaching 60G of original content. It contains hand coded HTMLs 2,
3, 4 & 5. It is a complete mess. Despite a long search, I could not
find any tools to properly identify its flaws. Anything I did find
was at most cursory.

Then came the cow flu*.

*corvid means crow, thus covid means cow**.

**by the rules of sympathetic spelling.

Unabashed Opportunism
If you appreciate modernist poetry or abstract photography, I’ve been
published. Click on books at arts & ego for gen.

written by dylan harris
September 2023


ssc - analyse static web site source

ssc [...] directory
ssc -f config

ssc (the Static Site Checker) is an opinionated HTML nit-picker,
intended for people, such as its author, who hand code websites. It
doesn't just check static websites for broken links, dubious syntax,
and bad semantic data, it will actively complain about things that are
perfectly legal but rather untidy, like its author.

Except when serving CGI queries, it recursively scans the directory
looking for HTML source files to analyse. It produces a list of errors,
warnings, comments, and other hints of imperfection. Once complete, it
summarises internal site inconsistencies, and can produce some simple

Scripts are ignored.


These options are only available on the command line:

-f file                 Load configuration from file, which should be
                        in .INI file format. See CONFIGURATION FILE
                        FORMAT below. This should be an absolute path.

-F                      Load the configuration file .ssc/config in the
                        current directory.

-h                      Show a summary of switches, then exit.

-H snippet              Only nitpick this snippet of html

--ontology.list         List known schema versions, then exit.

-V                      Show version details, then exit.

--validation            Show attribute extensions, then exit. Attribute
                        extensions are additional values that can be
                        associated with attributes on some X/HTML
                        elements, and is intended for use with bespoke
                        extensions of HTML.


These options are available on the command line (with dashes) and in
configuration files (without dashes). The short form alternative
switches only work on the command line.

Most binary options, e.g. those without arguments below that turn on a
feature (which may be the default), have a corresponding "no-" switch
to turn it off. The "no-" is inserted after the dot, so, for example,
the contradiction to "--general.class" is "". When
both are specified, perhaps in a configuration file and on the command
line, the "no-" switch always applies.

--corpus.article        Prefer the content of <ARTICLE> when gathering
                        corpus text.

--corpus.body           Prefer the content of <BODY> when gathering
                        corpus text. This is the default.

--corpus.main           Prefer the content of <MAIN> when gathering
                        corpus text.

--corpus.output file    Dump XML corpus of site into file. This is
                        intended for use by a local search engine. If
                        none of --corpus.article, --corpus.body, or
                        --corpus.main are specified, the content of
                        <BODY> is used. If more than one are specified,
                        then the text collected depends on a page's
                        content. This is incompatible with

--css.animation X       Use CSS Animation level X, where X is 0, 3 or 4

--css.background X      Use CSS Backgrounds and Borders level X, where
                        X is 0 or 3
                X       Use CSS Box Alignment level X, where X is 0 or
                        3 X       Use CSS Box Model level X, where X is 0, 3 or 4
                X      Use CSS Box Sizing level X, where X is 0 or 3

--css.cascade X         Use CSS Cascade level X, where X is 0, 3, 4, 5
                        or 6

--css.colour X          Use CSS Colour level X, where X is 0, 3, 4 or 5

--css.compositing X     Use CSS Compositing and Blending level X, where
                        X is 0 or 3

--css.cs X              Use CSS Counter Style level X, where X is 0 or

--css.custom X          Use CSS Custom Properties for Cascading
                        Variables level X, where X is 0 or 3

--css.display X         Use CSS Display level X, where X is 0 or 3

--css.ease X            Use CSS Easing Functions level X, where X is 0
                        or 3

--css.extension ext     Presume files with extension '.ext' are CSS

--css.fbl X             Use CSS Flexible Box Layout level X, where X is
                        0 or 3

--css.font X            Use CSS Fonts level X, where X is 0, 3, 4 or 5

--css.frag X            Use CSS Fragmentation level X, where X is 0, 3
                        or 4

--css.grid X            Use CSS Grid level X, where X is 0, 3 or 4
                        (since the specs confusingly use levels 1 and 2
                        for versions of CSS which are not CSS 1 nor
                        2.x, ssc accepts 1 for 3, and 2 for 4). X           Use CSS Media level X, where X is 0, 3, 4 or 5

--css.multi-column X    Use CSS Multi-Column level X, where X is 0 or 3

--css.namespace X       Use CSS Namespaces level X, where X is 0 or 3

--css.overflow X        Use CSS Overflow level X, where X is 0 or 3

--css.position X        Use CSS Positions level X, where X is 0 or 3

--css.selector X        Use CSS Selectors level X, where X is 0, 3 or 4

--css.shape X           Use CSS Shapes level X, where X is 0, 3 or 4

--css.speech X          Use CSS Speech level X, where X is 0 or 3 X           Use CSS Style level X, where X is 0 or 3

--css.syntax X          Use CSS Syntex level X, where X is 0 or 3

--css.text-dec X        Use CSS Text Decoration level X, where X is 0,
                        3 or 4

--css.transition X      Use CSS Transitions level X, where X is 0 or 3

--css.ui X              Use CSS Basic User Interface level X, where X
                        is 0, 3 or 4

--css.value X           Use CSS Values and Units level X, where X is 0,
                        3 or 4

--css.verify            Verify CSS files (replaces --general.css)

--css.version X         Presume version X of CSS, where X is one of:
                            1     CSS 1.0
                            2.0   CSS 2.0
                            2.1   CSS 2.1
                            2.2   CSS 2.2 (Feb 2022 draft)
                            3     all CSS level 3 (unfinished)
                            4     all CSS level 4 (unfinished)
                            5     all CSS level 5 (unfinished)
                            6     all CSS level 6 (unfinished)

--css.writing X         Use CSS Writing Mode level X, where X is 0, 3
                        or 4

--general.class         Nitpick class values

--general.classic       Report all classes used, not just those in
                        CSS files.

--general.cgi           Check environment variables for snippets of
-W                      HTML. SSC expects environment variables as
                        produced by OpenBSD's native httpd, produced
                        using <FORM METHOD=GET …>. Do NOT let ssc
                        anywhere near untrusted data. Ignores many
                        options such as shadowing.

--general.custom EL     Define a custom element <EL> for verifying the
                        IS attribute. May be repeated.

--general.datapath dir  Look for any configuration, caches, and other
-p dir                  useful files, in this directory.

--general.defthrd N     If --general.thread is not given, then set the
-N N                    number of threads to N.

--general.error x       If nits of the specified category or worse are
-E                      generated, then, on exit, return an error code.
                        Values are: 'catastrophe', 'error' (the
                        default), 'warning', 'info', or 'comment'.

--general.exclude REG   Ignore all files that match the posix regular
                        expression REG. May be repeated.

--general.file XXX      File for persistent data. Requires -N. See also
                        --general.datapath. Default extension: .ndx.

--general.git           Ignore git's internal files.

--general.ignore EL     ignore attributes and content of the element
                        <EL>. May  be repeated.          Report launch context when starting.

--general.lang LA       If an X/HTML file does not have a language /
                        dialect specified (e.g. "en" for generic
                        English, "en-IE" for Irish English, "lb-LU"
                        for Luxembourgish, "ma" for Marain, etc.),
                        default to 'LA'. If not given, the default is
                        your system default, or, if none, then "en-US"
                        (the standard American dialect of English).

--general.maxfilesize n Do not process HTML source files that exceed n
                        bytes in size (default: 4M). Specify 0 for
                        unlimited, although be warned that ssc is
                        stunningly stupid in such circumstances and may
                        even attempt to load files bigger than
                        available memory.

--general.output        Output to the specified file. If this switch is
-o file                 not used, standard output is used.

--general.progress      Dump progress information to standard output.
-D                      This can interfere with formatted output.

--general.rdfa          Check RDFa attributes.

--general.rel           Only mention <LINK> REL values, found neither
                        in the living standard nor at,
                        in debug output.

--general.rpt           Report CSS files that are opened.

--general.slob          Ignore perfectly legal yet inefficient, indeed
                        thoroughly slobby, HTML, such as being far too
                        lazy to get round to bothering to close

--general.spec          Reset the values of most switches to false.

--general.ssi           Process Server Side Includes (SSIs). Note ssc
-I                      cannot process SSIs directives with formulae.
                        Processing SSIs may cause incorrect line
                        numbers to be mentioned when an issue is

--general.test          Output data in automated test format. Used by
-T                      ssc-test. Not generally useful. Documented so
                        you can avoid it!

--general.thread N      Use N threads when running. Defaults to a value
-n N                    appropriate for the hardware. Too high a value
                        can cause problems. See also --general.defthrd.

--general.verbose x     Output nits to the specified verbosity:
-v                      'catastrophe', 'error', 'warning', 'info',
                        'comment' (the default), or '0' for silence.
                        Additional values are available when debugging.
                        Each level includes its preceding level, so,
                        for example, 'warning' will also output
                        'catastrophe' and 'error' nits.

--html.force            If <!DOCTYPE. …> is missing, force presumption
                        of --html.version value, not HTML 1/tags

--html.rfc1867          Ignore the RFC 1867 (INPUT=FILE) extension when
                        processing HTML 2.0

--html.rfc1942          Ignore the RFC 1942 (tables) extension when
                        processing HTML 2.0.

--html.rfc1980          Ignore the RFC 1980 (client side image maps)
                        extension when processing HTML 2.0.

--html.rfc2070          Ignore the RFC 2070 (internationalisation)
                        extension when processing HTML 2.0.

--html.tags             When an HTML file is loaded that contains no
                        DOCTYPE, ssc normally presumes HTML 1. This
                        switch tells it to presume the file conforms
                        to an earlier HTML Tags specification (the one
                        at CERN). This is overridden by --html.version.

--html.title n          If <TITLE> text is longer than n characters,
-z n                    say so. This applies to text enclosed by a
                        <TITLE> element under <HEAD>, not the value of
                        TITLE attributes.

--html.version X        If no doctype (or xml header) is specified,
                        presume version X of HTML. X can be:
                            tags  HTML tags (1991, informal)
                            1     HTML 1.0 (Jun 1993 draft)
                            1.0   HTML 1.0 (Jun 1993 draft)
                            +     HTML Plus (Nov 1993 draft)
                            2     HTML 2.0
                            2.0   HTML 2.0
                            3     HTML 3.2
                            3.0   HTML 3.0 (Mar 1995 draft)
                            3.2   HTML 3.2
                            4     HTML 4.01
                            4.0   HTML 4.0
                            4.1   HTML 4.01
                            4.2   XHTML 1.0
                            4.3   XHTML 1.1 core
                            4.4   XHTML 2.0 (Dec 2010 draft)
                            5     recent WhatWG HTML 5
                            5.0   W3 HTML 5.0
                            5.1   W3 HTML 5.1
                            5.2   W3 HTML 5.2
                            5.3   W3 HTML 5.3 (Oct 2018 draft)

                            2005/1/1    WhatWG WebApps draft (Jan 2005)
                            ...         (halfly)
                            2007/1/1    WhatWG WebApps draft (Jan 2007)
                            2007/7/1    WhatWG HTML 5 (Jul 2007)
                            ...         (halfly)
                            2021/1/1    WhatWG HTML 5 (Jan 2021)
                            ...         (quarterly)
                            2023/7/1    WhatWG HTML 5 (Jul 2023)

                            XHTML 1.0   XHTML 1.0
                            XHTML 1.1   XHTML 1.1 core
                            XHTML 2.0   (Dec 2010 draft)
                            XHTML 5.x   XHTML corresponding to
                                        equivalent W3 HTML

                        Although you can specify exact dates for
                        versions of the WhatWG HTML 5 living standard,
                        currently only broad versions published in
                        January and July are supported (quarterly
                        from 2021).

                        Certain versions of HTML offer variants, such
                        as loose and strict definitions. ssc picks
                        those up from the <!DOCTYPE …> in the HTML
                        file, if any, and then carefully ignores them.

                        Validation of XHTML is even less strict.

                        Just to remind you, there are no guarantees of
                        accuracy (or inaccuracy).

                        Copies of the appropriate standards can be
                        found online. A copy of the copies referenced
                        during ssc's development can be found at

--link.301              Normally, when ssc checks external links
-3                      (--link.external), it does not report http
                        forwarding errors 301 and 308. Use this switch
                        to have it do so.

--link.check            Check internal links, e.g. those within the
-l                      website being analysed.

--link.example          Report links to faux domains, as defined by RFC
                        2606 (note ssc also reports links to
              , &

--link.external         Check external links, e.g. those not on the
-e                      site being checked. Note that ssc will NOT
                        check RFC 2606 links, such as (see

--link.forward          Report HTTP forwarding errors encountered when
                        checking external links (e.g. 301 and 308)

--link.ignore DOMAIN    When checking external links, ignore this
                        domain. May be repeated.

--link.local            Report links to local domains, such as domains
                        ending in .lan, .home, .corp, and others.

--link.once             Only report each broken external link once. If,
-O                      for example, the site has a number of references
                        to a page that does not exist, ssc will only
                        report the first instance of the broken link.
                        Note that, even if it reports every occurrence
                        of the link, it will only check it the first
                        time it's encountered (requires

--link.pretend FILE     When checking local files, pretend this file
                        exists. DOMAIN    Report links to domain and its descendents. May
                        be repeated.

--link.revoke           Do not check whether links' https certificates
-r                      have been revoked (requires --link.external).

--link.xlink            Check crosslink IDs on the site being analysed.
-X                      For example, if a link goes to /index.html#id,
                        then, when this switch is set, ssc will verify
                        that the id exists and that it is not hidden.

--math.core             Presume Math 4 core (May 2022 draft).

--math.draft D          Presume this draft of MathML 4. The following
                        drafts supported:
                                2020    December 2020 draft
                                2022    August 2022 draft

--math.version N        Presume version N of MathML (1, 2, 3 pr 4). The
                        following versions are supported:
                                0   try to work it out from the (HTML)
                                    version of the file being analysed
                                1   MathML 1
                                2   MathML 2
                                3   MathML 3
                                4   MathML 4 (see --math.draft)

--microdata.export      Export microdata encountered. This
                        data is exported in JSON format (not JSON-LD).

--microdata.root DIR    When exporting microdata with
                        --microdata.export, write files into the
                        directory DIR. ssc will create the directory
                        tree structure as appropriate.

--microdata.verify      Check microdata found in WhatWG microdata
-m                      attributes (itemprop, itemtype, etc.). Note
                        that ssc only knows about certain ontologies
                        (see --ontology.list)

--microdata.virtual v=d When exporting microdata using
                        --microdata.export, export the contents of
                        virtual directory 'v' to 'd'. 'v' must match a
                        directory identified with --site.virtual. For
                            --microdata.virtual virtual=X:\virtual.

--microformat.export    Export microformat data encountered in JSON
                        format. This option will write files in the
                        same directory as the source, with the
                        extension .json.

--microformat.verify    Verify Microformats data in class and rel
-M                      attributes (see

--microformat.version x Presume microformats version x. The following
                        values are currently accepted:
                                1   microformats version 1 only
                                2   microformats version 2 only
                                3   both microformats versions 1 and 2

--nits.catastrophe n    redefine nit n as a catastrophe; may be
                        repeated (the value of n can be determined
                        using --nits.nids below).

--nits.comment n        Redefine nit n as a comment; may be repeated
                        (the value of n can be determined using

--nits.debug n          Redefine nit n as a debug message; may be
                        repeated (the value of n can be determined
                        using --nits.nids).

--nits.error n          Redefine nit n as an error; may be repeated
                        (the value of n can be determined using

--nits.extra            Report additional nits.

--nits.format F         Specify the output format; F is a template
                        file (see OUTPUT TEMPLATE below). n           Redefine nit n as information; may be repeated
                        (the value of n can be determined using

--nits.nids             Output nit ids, which can be used to redefine

--nits.override F       Use this output format, not the one specified
                        by --nits.format. F is a template file (see
                        OUTPUT TEMPLATE below). This switch is intended
                        to aid automation.

--nits.quote X          Specify quote style when using nit.format. X
                        can be 'text' or 'html'.

--nits.root             By default, seek nit output template files in
                        the website root.

--nits.silence n        Silence nit n; may be repeated (the value of n
                        can be determined using --nits.nids).

--nits.unique           Do not output repeated nits, even if they may
                        contain additional information.

--nits.warning n        Redefine nit n as a warning; may be repeated
                        (the value of n can be determined using
                        --nits.nids).            Output debug nits (intended for automation).

--rdfa.version          When checking RDFa files, presume this version
                        (default: 1.1.3). Note, RDFa analyis is
                        incomplete, and only intended for supporting
                        HTML analysis.

--ontology.ONT X.Y      Presume version X.Y of ontology ONT. For
                            --ontology.xsd 1.1
                        defaults usage of XSD to version 1.1. The
                        versions apply to RDFa, microdata, and
                        microformats (using class) analysis. If .Y is
                        omitted, .0 is presumed. X must be present.
                        Unspecified defaults are derived from the HTML
                        version. For a list of possible values, use

                        At the time of writing, the following ontology
                        versions can be verified. Note that single
                        version ontologies cannot have their version
                                adms 1.0,2.0
                                article 12,14,18,22
                                as 1.0,2.0
                                basic 1.0-1.3,2.1,3.0 (see below)
                                bfo 2.0,2020 (see below)
                                bibo 1.3
                                biro 1.1
                                book 12,14,18,22
                                cc 1.0
                                cito 2.8
                                content 1.0
                                crs 1.0 (see below)
                                csvw 1.0
                                ctag 1.0
                                daq 1.0
                                ddi 1.0
                                dbp 1.0
                                dbp-owl 1.0
                                dbr 1.0
                                dc11 1.0,1.1
                                dcam 1.0
                                dcat 1.0,2.0
                                dcmi 1.0
                                dcterms 1.0,1.1
                                ddi 1.0
                                doap 1.0
                                dqv 1.0
                                describedby 1.0
                                duv 1.0
                                earl 1.0
                                event 1.0
                                exif 1.0-3.0 (see below)
                                exifex 2.21-3.0 (see below)
                                foaf 0.1-0.99
                                frbr_core 1.0
                                gr 1.0
                                grddl 1.0
                                gs1 1.1-1.5
                                ical 1.0
                                icaltzd 1.0
                                jsonld 1.0,1.1
                                ldp 1.0
                                license 1.0
                                locn 1.0
                                ma 1.0
                                mf 1.0-2.255
                                music 12,14,18,22
                                oa 1.0
                                odrl 1.0
                                og 10,12,14,18,22 (see below)
                                org 1.0
                                owl 1.0,2.0
                                pam 2.0 (see below)
                                pcm 3.1 (see below)
                                pcmm 3.0 (see below)
                                pcv 1.0(see below)
                                pdf 1.0 (see below)
                                photoshop 1.0 (see below)
                                pim 1.0-3.0 (see below)
                                pmi 3.0 (see below)
                                poetry 1.0,1.1
                                prism 1.0-3.0 (see below)
                                prism-ad 3.0 (see below)
                                prl 1.0-2.0 (see below)
                                prm 3.0 (see below)
                                prs 3.1 (see below)
                                profile 12,14,18,22
                                prov 1.0
                                psv 1.0 (see below)
                                ptr 1.0
                                pur 2.1-3.0 (see below)
                                qb 1.0
                                rdf 1.0-1.3
                                rdfa 1.0-1.3
                                rdfg 1.0
                                rdfs 1.0
                                rev 1.0
                                rif 1.0
                                role 1.0
                                rr 1.0
                                schema 0.10-22.0 (see below)
                                sd 1.0
                                sioc 1.0
                                sioc_s 1.0
                                sioc_t 1.0
                                skos 1.0
                                skosxl 1.0
                                sosa 1.0
                                ssn 1.0
                                stdim 1.0 (see below)
                                stevt 1.0 (see below)
                                stfnt 1.0 (see below)
                                stjob 1.0 (see below)
                                stref 1.0 (see below)
                                stver 1.0 (see below)
                                taxo 1.0
                                tiff 6.0
                                time 1.0
                                v 1.0
                                vann 1.0,1.1
                                vcard 1,2,3,4 (see below)
                                video 12,14,18,22
                                void 1.0
                                wdr 1.0
                                wdrs 1.0
                                website 12,14,18,22
                                wwg 1.0
                                xhv 1.0
                                xml 1.0
                                xmp 1.0 (see below)
                                xmpdm 1.0 (see below)
                                xmpg 1.0 (see below)
                                xmpgimg 1.0 (see below)
                                xmpidq 1.0 (see below)
                                xmpmm 1.0 (see below)
                                xmprights 1.0 (see below)
                                xmptpg 1.0 (see below)
                                xsd 1.0,1.1

                        The various Adobe ontologies (crs, pdf,
                        photoshop, stdim, stevt, stfnt, stjob, stref,
                        stver, smp, xmpdm, xmpg, xmpgimg, xmpidq,
                        xmpmm, xmprights, xmptpg) have only been
                        partially applied. They do not seem to have
                        been designed for microdata, hence the partial
                        implementation: the goal is to enable hoovering
                        to JSON.

                        BFO (Basic Format Ontology) versions should be
                        specified as follows:
                                Use         For
                                2.0         2.0
                                2.2         2020

                        BFO 2020 uses OBO's machine code style
                        identifiers. Given the history of computing
                        science, as a convenience for users, and with
                        my experience of both devops and maintaining
                        code, identifiers following the standard
                        ontology naming convention are also accepted.
                        Since this is unofficial, both standard English
                        and American dialects' spellings are processed.

                        The Exif & ExifEx ontologies have the following
                            Use     For
                            1.0     1.0 (exif only)
                            1.1     1.1 (exif only)
                            2.0     2.0 (exif only)
                            2.10    2.1 (exif only)
                            2.20    2.2 (exif only)
                            2.21    2.21
                            2.30    2.3
                            2.31    2.31
                            2.32    2.32
                            3.0     3.0
                        Manufacturers' extensions to EXIF are omitted,
                        with exceptions.

                        Open Graph versions correspond to snapshots of
                        the specs from 2010, 2012, 2014, 2018 & 2022.

                        The various Prism ontologies (pam, pamp, pcm,
                        pcmm, pcv, pim, pmi, prism, prism_ad, prl, prm,
                        prs, psv, pur) have only been partially
                        applied: some specifications are unavailable,
                        some specifications break HTML5 syntax. Prism
                        was not designed for microdata, hence the
                        partial implementation: the goal is to enable
                        hoovering to JSON.

                        Most versions of schema ( should be
                        specified by their version number, but this
                        doesn't work with early versions, which should
                        be specified a follows:
                                Use         For
                                0.10        June 2011
                                0.15        July 2011
                                0.20        August 2011
                                0.25        September 2011
                                0.30        October 2011
                                0.35        November 2011
                                0.40        December 2011
                                0.45        January 2012
                                0.50        February 2012
                                0.55        March 2012
                                0.60        April 2012
                                0.91-0.99   as version number
                                1.0         1.0a
                                1.1         1.0b
                                1.2         1.0c
                                1.3         1.0d
                                1.4         1.0e
                                1.5         1.0f
                                1.10        1.1
                                1.20        1.2
                                1.30        1.3
                                1.40        1.4
                                1.50        1.5
                                1.60        1.6
                                1.70        1.7
                                1.80        1.8
                                1.90        1.9
                                1.91        as version number
                                22.0        as version number

                        vCard versions correspond to RDFa specs,
                        published in 2001, 2006, 2010 & 2014. They do
                        NOT correspond to vCard data format

--shadow.changed        When shadowing a site that has been previously
                        shadowed, only copy/link files that have

--shadow.comment        Do not delete comments when writing shadow

--shadow.copy X         Create a shadow directory structure from source
                        HTML files, with errors removed and some things
                        tidied up. X can be:
                                no     copy nothing (default)
                                pages  write 'fixed' source files,
                                       ignore non source files
                                hard   set up hard links to non-source
                                       files (requires source and
                                       shadow directories to be on the
                                       same disk) (see below)
                                soft   set up soft links to non-source
                                       files (see below)
                                all    copy non HTML files too
                                dedu   copy non HTML files too, but
                                       deduplicate them, changing links
                                       in HTML source if necessary (see
                                report report duplicates (no
                        ssc cannot convert between versions of HTML,
                        nor between HTML and XHTML.
                        Link options are only available on systems that
                        support links.

--shadow.enable         Enable shadowing (set by other shadow options).
                        If shadowing is enabled, but shadow.root is not
                        set, SSC will litter the site source
                        directories with .ndx files.

--shadow.file f         Write ssc's shadow cache to file f, to
                        accelerate future shadowing of the same
                        content updated.

--shadow.ignore ext     When shadowing, ignore files with this
                        extension (may be repeated).           Add a comment at or near the top of each
                        shadowed HTML file noting its generation time.

--shadow.msg text       Insert a comment containing text at the top of
                        each generated page. Note that, if any SSI
                        include file is updated, the comment will
                        appear whether or not the original page has

--shadow.root dir       Where to write the shadowed site.          Leave excess/repeated spaces and blank lines in
                        the shadowed files untidily untouched.

--shadow.ssi            Do NOT resolve Server Side Includes when
                        shadowing, even if --general.ssi is set.

--shadow.update         Only examine files that have changed since the
-u                      last time ssc ran. This is incompatible with
                        --corpus.file. This requires --shadow.file.
                        Nits of files that have not changed will not be

--shadow.virtual v=d    When shadowing virtual directories, output the
                        shadow of virtual directory 'v' to directory
                        'd'. 'v' must match a directory set up using

--site.domain domain    The domain name of the site is 'domain'. This
-S domain               can be repeated. This is used to identify any
                        URL that is apparently external but is actually
                        internal to the site.

--site.extension ext    Treat files with this extension as X/HTML
-x ext                  source files. This may be repeated. Files with
                        extension .html are always checked.

--site.index file       This is the name of the default file in a
-i file                 directory. This can be repeated. This is used
                        for checking internal links.

--site.root dir         This is the root of the website to analyse. ssc
-g dir                  will recursively scan the directory analysing
                        any HTML files it finds. The default is the
                        current directory.

--site.virtual v=d      The virtual directory 'v' is located in actual
-L v=d                  directory 'd' on the local filesystem. For
                            --site.virtual virtual=D:\actual

--spell.accept XXX      XXX is a correct spelling of a word (or a list
                        of words) in all languages.

--spell.cased           Nitpick correctly spelt but wrongly cased

--spell.check           Check text spelling. Uses external spelling
                        checkers, so results will be inconsistent
                        between systems.

--spell.dict LANG,DICT  Unix only. Associate dictionary DICT with LANG.
                        For example, if the standard English dictionary
                        is en_GB-large:
                            --spell.dict en-GB,en_GB-large
                        (Under Windows, ssc uses the OS dictionaries.)             If "no", do not use the ICU libraries at all
                        (they are rather slow). This will increase the
                        inaccuracy and incorrectness of the spell checks.

--spell.list FN,LANG    The file FN contains a list of valid spellings
                        for language LANG (which may include country
                        info). If LANG is omitted, the valid spellings
                        apply to all languages. For example:
                            --spell.list villages.txt,en-IE
                            --spell.list dorfer.txt,de
                            --spell.list letzstied.txt

--spell.path PATH       Unix only. Path to spelling executable.
                        Hunspell or a compatible program is expected.
                        If none is specified, ssc will seek hunspell.
                        (Under Windows, ssc uses the OS spellchecker.)

--stats.export F        Export stats to file F.

--stats.meta            Produce statistics on <MET> usage in <HEAD>.
                        Note that pragmas reported (http-equiv) are
                        those found in the HTML source, not those
                        returned by the HTTP protocol. Remember that
                        many web servers (not all) will remove some
                        pragmas when serving pages.            Produce statistics for each source file

--stats.summary         Produce a summary of overall statistics for the

--svg.version x         Presume any SVG code encountered is this
                        version, unless the SVG code itself specifies a
                        version. Versions recognised:
                            1.2      (really 1.2/tiny)
                            1.2/full (May 2004 draft, incomplete, any
                                      conflict with 1.2/tiny always
                                      resolves in favour of 1.2/tiny)
                            2.1 (April 2021 draft)
                        If this switch is not used, and some SVG code
                        does not identify its version, the version is
                        derived from the version of the host X/HTML

--validation.attribute ATT
                        Add the custom attribute ATT. This attribute
                        will be ignored, not validated.

--validation.charset CH Accept CH as a charset. May be repeated.

--validation.class CL   Add the valid class CL. May be repeated.

--validation.color COL  Accept COL as a colour. May be repeated.

--validation.colour COL Accept COL as a colour. May be repeated. CC Accept CC as a valid two-letter country code.
                        May be  repeated.

--validation.currency CUR
                        Accept CUR as a valid currency. May be

--validation.element EL Accept <EL> as a valid element. This element
                        will be ignored, not validated. May be

--validation.element-attribute EL,ATT
                        Accept the known attribute ATT on the element
                        <EL>. Doesn't work with namespaces (names
                        containing ':'). May be repeated.

--validation.extension EXT
                        Accept the extension EXT as a mimetype file
                        extension. May be repeated.

--validation.ff FEATURE Accept FEATURE as a CSS font feature. These
                        should normally be four characters long. May be

--validation.ff VARIATION
                        Accept VARIATION as a CSS font variation. These
                        should normally be four characters long. May be

--validation.httpequiv HEQ
                        Accept HEQ as a valid macro for httpequiv on
                        <META> elements. May be repeated.

--validation.lang LANG  Accept LANG as a valid language code. May be

--validation.minor x    When validating W3 HTML 5 source code, using
-m x                    this minor version of W3 HTML 5. Valid values
                        are 0, 1, 2, and 3 (draft). WhatWG versions are
                        determined by date, corresponding roughly to
                        the date of the (online) publication of the
                        specific version. See the --html.version

--validation.metaname M
                        Accept M as valid for the NAME attribute of the
                        <META> element. The VALUE will be ignored. May
                        be repeated.

--validation.microdata  Validate ( microdata.

--validation.mimetype MT
                        Accept MT as a valid mimetype. May be repeated.

--validation.sgml SGML  Accept SGML as a valid SGML schema
                        identification (as found in <!DOCTYPE …>). May
                        be repeated.

--validation.XXX YYY    Accept YYY as a valid value for attribute type
                        XXX. For a list of possible values of XXX, use
                        the command line switch --validation.


If a configuration file is used, it should be in INI file format. All
content is optional.

Section and option names are derived from the long form switch name,
which consists of --SECTION.OPTION, laid out in the format:


Switches that do not have a long form version cannot be used in a
configuration file.

Each ssc test (in the recipe/toast folder) has a configuration file;
browse them for examples.


If you set --general.cgi, ssc will check these environment variables:

QUERY_STRING            Run under OpenBSD's httpd server. See notes
SSC_CONFIG              If no configuration file is given on the
                        command line, use this one
SSC_ARGS                Preliminary command line parameters

If, when SSC is run, the environment variable QUERY_STRING is set to an
OpenBSD httpd server CGI value that includes the parameter
html.snippet, then SSC will nitpick that snippet only. Some other
parameters are processed, including general.verbose and html.version.


If no significant nits are found, ssc exits with 0, otherwise it exits
with a value > 0. See the --general.error switch.


The --nit.format switch allows control of output format. It takes a
file name. The format of that text file is a sequence of fixed section
names, enclosed in square brackets on their own lines, each optionally
followed by text. In that text, certain specific identifiers, enclosed
in brace pairs, are substituted. For example:

My pet dog {{dog-name}} is a {{bad-dog}}.

For examples, browse recipe/toast/output/*.nit

If no file is specified, or if the file cannot be loaded, a default
template is used.

Note also the --nit.quote switch.


To verify the version of ssc:
ssc -V

To check the static web side source directory /home/site/wwwroot:
ssc /home/site/wwwroot

To check a static HTML/XHTML website for, that uses server
side includes, in the current directory, with verification of external
links, with rather verbose output:
ssc -e -I -x html -x shtml -s -v 5 -i index.shtml

To check a static web side in the current directory, with a virtual
directory, verifying microformats:
ssc -L vitual=/home/site/virtual -M

To check a static web site using a configuration file:
ssc -f config.file

A simple configuration file might contain:


A configuration file to check a site against HTML 5.2 and SVG 1.1 might


A configuration file to check against a particular WhatWG living
standard, gathering statistics:


A configuration file to shadow copy and deduplicate a site might


A configuration file to export microdata preparing against
version 7.2 might contain:



These files are based on the steps I take to update an OpenBSD website.

Presume a directory containing the following:
site.conf    ssc configuration file for a website
site         shadow output produced by ssc

Then I run a script like this:

ssc -f site.conf site /var/www/site-upload server user 0
ssh user@server "cd /var/www ; mv site x ; mv site-upload site ;
mv x site-upload ; ln -sf site htdocs" is a macos bash script that can be found among the source
code. Note that I have rather naughtily replaced OpenBSD's httpd
document directory /var/www/htdocs with a link.

Here is site.conf:











ssc ( is written by Dylan Harris (

known issues

SSC is α software. It doesn’t do what it’s supposed to do, and what it’s supposed to do is wrong.

Note that github hosts a list of known issues.

* How can such a dangerous animal have such a cuddly name? It’s like calling a Hound of Hell ‘Fluffy’, or Death’s horse Binky.

bug reporting

SSC is α software. It may contain unexpected features. If you encounter such a delight, please help improve ssc by collecting the following information (where relevant):

and emailing everything to (if the collected files are more than small, please use a public fileserver and email the link). Do NOT send anything confidential. Furthermore, unless you request otherwise, we reserve the right to publish some or all of the information sent in future versions of ssc, usually in the test suite. If you have a fix, you are invited to submit a pull request on github. Thank you.


static site checker
(c) 2020-2023 Dylan Harris

SSC can be built on various unii with CMake and gcc or clang,
supporting C++ 17 or better, or with Visual Studios 2017 / 2019 / 2022
under Windows. I have built & tested a 64-bit version in selected OSs
on intel/amd & arm64 (m2) architecture. For now, the arm solution
should be seen as particularly hopeless.

Although ssc builds and runs with older compilers on older systems, not
all features are available on them.


Common dependencies
You need boost version 1.75 or better (, a recent
version of the ICU libraries (, Microsoft's
GSL library ( (or define NO_GSL), and
a recent version of libcurl (*. Usually, an Operating
System's package system has an appropriate version ready to install.

*libcurl requires a thread-safe underlying SSL library: see

You may need to set these environment variables:
- BOOST: if you're not using your operating system's packaged flavour
  of boost, then set BOOST to your boost source root directory;
- ICU_ROOT: if you're not using your operating system's packaged ICU,
  set ICU_ROOT to your ICU source root directory;
- GSL: set it to your GSL root directory.

Building SSC under unii, including macos, requires a development
installation of hunspell (

Once you've got them, you can run cmake from the project root

The Windows build, by default, uses the native Windows spellchecker,
although, except for Windows 11, that doesn't seem to work so well in
multilingual contexts.


To build from Visual Studio, navigate to recipe/tea, open the
appropriate .sln file, then build. Only Visual Studios 2017 / 2019 /
2022, 64 bit, have been built & tested, for intel and arm64, under
Windows 10 & 11. I've not built ssc using CMake under Windows.

Note the included solutions presume Microsoft's VCPKG manager. There
are alternatives.

On low memory build machines, disable the /MP switch.

Unii & mock Unii
You will need CMake 3.19 or better. On Linux, you will also need
lsb-release. These can be found in most distributions' standard
packages. (For macos, I used macports, but brew is good too.)
From the home ssc directory, compile a normal build thus:
cmake .
make install

For a debug build:
cmake -DCMAKE_BUILD_TYPE=Debug .
make install

If everything works correctly, then everything will be built, a series
of tests run, with a final result at the very end saying no failures.
Having said that, given SSC is alpha, don't be too surprised to see
some warnings or some final test errors. Note in particular that
complaints about being unable to find or copy files during testing are
not of concern, these come from scripts that set up or tear down
individual tests, and the standard commands used sometimes complain if
they can't find files they're supposed to delete, which is a bit silly
given that means things are already in the desired state.

The following have been successfully built as x64 amd/intel:
FreeBSD:  12.3 / 13.1
Linux:    Alma Linux 9, AOSC, Centos 8 / 9, SUSE Tumbleweed,
          Ubuntu 20.04 / 22.04
MacOS:    Ventura, Monterey, Big Sur, Catalina, Mojave, High Sierra,
          Sierra, El Capitan, and Yosemite
OpenBSD:  7.3 / 7.2 / 7.1 / 7.0 / 6.9 / 6.8

The following have been successfully built as arm64:
Linux:    Centos 9
MacOS:    Ventura

A build on an older operating system may result in some features being

Centos 9
The appropriate CMake command is:
  cmake . -DFLAVOUR=CentosOSStream -DFLAVOUR_VER=9
(beware the standard English spelling of flavour.)

You may need to increase significantly the available memory setting
for your build account in login.conf.

clang vs. gcc
For now, if you can, use gcc, not clang. There is a crash in clang
built versions of ssc that is not exhibited by gcc or msvc built
binaries. I have yet to find it, so do not know whether this is a bug
in the compiler, or a bug in ssc that is only exposed by clang. To see
the problem, run ssc against the wpt test-suite from the 2023 summer
solstice, which can currently be found at github.

The problem is often avoided at runtime with the -N 1 switch.

If you do use clang, the environment variable SANITY can be used to
apply one of its sanitiser tests. Details of those tests can be found


Under Visual Studio, run ssc??-test using these arguments:

  -v -x $(ProjectDir)..\..\ssc.exe
    -f $(ProjectDir)..\toast\ssc-test\win.lst
(all one line)

Add '-d' if you want the test utility to retain intemediate files.

Under CMake, run ctest:
  ctest -V
(which runs ssc-test for you, using nix.lst).

The testing utility is rather dim; it will test features that are not
built, causing failures.

Spelling test results depend on the dictionaries installed.

Supporting libraries

If you can't find a copy of Microsoft's GSL in your system's standard
package suite, then grab a current copy from its github repository
(, then unpack, build and install it.
In Windows, remember to add its root directory to your local path.

This is in every standard unix flavour repository that I've met, but
not so easy for Windows. I suggest the following:

1  Install the Microsoft repository vcpkg (
2  Run up the visual studio 64bit native command prompt
3  Run the vcpkg bootstrap batch file, noting the comments
4  Enter "vcpkg install curl:x64-windows"
5  Add an environment variable to your account for CURL, perhaps:
6  Add the installation bin directory to your local path, perhaps:
7  If you plan to debug, also add debug\bin, perhaps:

Adapt the architecture as necessary. If you omit it, vcpkg might
carefully ignore your hardware and install x86.

Boost is to C++ as breakfast is to the working day.

Most package managers support it, including vcpkg. Many people build
their own versions using the sources found at


If everything works correctly, then everything will be built, a series of tests run, with a final result at the very end saying no failures. Having said that, given SSC is α, don’t be too surprised to see some warnings or some final test errors. Worse, some tests have dependencies that are vary across systems, which can cause spurious test failues.








































































































boot notes

Notes on folder names:

These reference documents are hoovered from various open source sites. They’re collected here for convenience; at all times the originals are correct. The subjects are: aria, activity streams, bibo, creative commons, charsets, content (RDF), content security policy, cascading style sheets, csvw, common tag, dataset quality, dbpedia, dublin core, data catalogue, did, document object model, domain, data quality, data usage, earl, ebu, fibo, foaf, good relations, grddl, HTML 1, HTML 2, HTML 3, HTML 4, HTTP, ical, its, javascript, json, lang, link relations, locn, ma-ont, marinetlo, mathML, media capture, microdata, mime, music, ns, web annotation, odrl, open graph, ontologies, openmath, org, other, owl, p3p, powder, prov, pso, qb, rddl, RDFa, RDFa, rif,, sd, sioc, skos, sm, smil, smpte, sosa, ssn, svg, time, ttml, url, vann, vcard, void, W3, webgl, webmention, whatwg, XHTML, xhv, XML, xsd, xsl, XSLT.

copyright & licence

Any dispute shall be resolved in accordance with the law of the Grand Duchy of Luxembourg.


SSC, static site checker,
copyright (c) 2020-2023 dylan harris

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.

You should have received a copy of the GNU General Public
License along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA


Some test files come from (some directly, in W3 documents, etc.), and are licensed as follows:


By obtaining and/or copying this work, you (the licensee) agree that you have read, understood, and will comply with the following terms and conditions.

Permission to copy, modify, and distribute this work, with or without modification, for any purpose and without fee or royalty is hereby granted, provided that you include the following on ALL copies of the work or portions thereof, including modifications:

    The full text of this NOTICE in a location viewable to users of the redistributed or derivative work.
    Any pre-existing intellectual property disclaimers, notices, or terms and conditions. If none exist, the W3C Software and Document Short Notice should be included.
    Notice of any changes or modifications, through a copyright statement on the new code or document such as
    "This software or document includes material copied from or derived from [title and URI of the W3C document]. Copyright © [YEAR] W3CÆ (MIT, ERCIM, Keio, Beihang)."




The name and trademarks of copyright holders may NOT be used in advertising or publicity pertaining to the work without specific, written prior permission. Title to copyright in this work will at all times remain with copyright holders.

This version:

Previous version:

This version makes clear that the license is applicable to both software and text, by changing the name and substituting "work" for instances of "software and its documentation." It moves "notice of changes or modifications to the files" to the copyright notice, to make clear that the license is compatible with other liberal licenses.


Some test files come from (some directly, in WhatWG documents, etc.), and are licensed under a Creative Commons Attribution 4.0 International License. See for details.

Some test files are derived from pages at They are licensed under a Creative Commons Attribution 4.0 International License. Browse for details.

Some test files are derived from pages at They are licensed under a Creative Commons Attribution 4.0 International License. Browse for details.