generated: '2026-09-07'
method: probed
source: https://jigsaw.w3.org/css-validator/
summary: >-
  The CSS Validation Service is itself a public console: three forms — by URL, by file upload,
  and by direct input — let anyone run a real validation with no account and no key. There is
  no separate sandbox because there is no live/test distinction to draw: the service is
  read-only and free, so the console and production are the same surface.
console:
  url: https://jigsaw.w3.org/css-validator/
  http_status: 200
  auth_required: false
  modes:
    - name: Validate by URL
      description: Enter the URL of an HTML or CSS document. @import rules are followed.
    - name: Validate by file upload
      description: >-
        Upload a local file. CSS only — HTML uploads are rejected — and @import is followed
        only when it references a public URL, so relative paths will not resolve.
    - name: Validate by direct input
      description: >-
        Paste a CSS fragment into a textarea. W3C recommends this mode for test cases and bug
        reports because the resulting URL is linkable.
  source: https://jigsaw.w3.org/css-validator/manual.html
test_mode:
  separate_test_environment: false
  test_credentials: []
  test_fixtures: []
  detail: >-
    No test keys, no test-vs-live prefixes, no fixtures and no time simulation, because none
    of those concepts apply — the service holds no state and issues no credentials.
live_probe:
  url: https://jigsaw.w3.org/css-validator/validator?text=a%7Bcolor%3Ared%7D&output=json&profile=css3
  http_status: 200
  fetched: '2026-09-07'
  result: 'validity true, errorcount 0, warningcount 0'
  note: >-
    A real anonymous call made during this pass. Recorded as the evidence that the console
    and the programmatic interface are the same unauthenticated surface.
local_alternative:
  detail: >-
    For anything beyond occasional interactive use, W3C directs callers to the jar rather than
    the hosted console. See cli/css-cli.yml.