Validator.nu Web Service Interface

Validator.nu can be called as a Web service. Input and output modes can be chosen completely orthogonally. Responses can be optionally compressed.

Input Modes

For most Web service use cases, you should probably POST the document as the HTTP entity body.

Implemented

• Document [Validator.nu GET Input|URL as a GET parameter]; the service retrieves the document by URL over HTTP or HTTPS.
• Document POSTed as the HTTP entity body; parameters in query string as with GET.
• Document POSTed as an application/x-www-form-urlencoded form field value.
• Document POSTed as a multipart/form-data file upload.

Not Implemented

• Document in a data: URI as a GET parameter.

Output Modes

When using Validator.nu as a Web service back end, the XML and JSON output formats are recommended for forward compatibility. The available JSON tooling probably makes consuming JSON easier. The XML format contains XHTML elaborations that are not available in JSON. Both formats are streaming, but streaming XML parsers are more readily available. XML cannot represent some input strings faithfully.

Implemented

• HTML with microformat-style class annotations (default output; should not be assumed to be forward-compatibly stable).
• XHTML with microformat-style class annotations (append &out=xhtml to URL; should not be assumed to be forward-compatibly stable).
• XML (append &out=xml to URL).
• JSON (append &out=json to URL).
• Human-readably plain text (append &out=text to URL; should not be assumed to be forward-compatibly stable for machine parsing).

Not Implemented

• GNU error format (needs a better spec)
• Relaxed-compatible (lacks a spec)
• Unicorn-compatible (hoping that Unicorn changes instead)
• W3C Validator-compatible SOAP (legacy)
• EARL (not implemented; domain modeling mismatch)