Signal handling
looks for navigator.globalPrivacyControl / Sec-GPC in inline scripts, the site’s own JS files and edge/serverless functions in the build (functions/, middleware). Do Not Track-only handling is called out.
GitHub Packages · MIT · Node ≥ 18
gpc-warden
Check that your built site honours Global Privacy Control: it reads the signal and suppresses sale/share trackers when it is on.
Check your built site honours Global Privacy Control: code reading navigator.globalPrivacyControl / Sec-GPC, sale/share advertising trackers that load unconditionally, /.well-known/gpc.json validity and policy disclosure. CCPA/CPRA, Colorado, Connecticut. SARIF, allowlist with expiry, GitHub Action. Zero deps.
1 Point the
@mrlouiswrightscope at GitHub Packages in.npmrc@mrlouiswright:registry=https://npm.pkg.github.com2 Install
npm i -D @mrlouiswright/gpc-warden
Installing from GitHub Packages needs a token
Published to GitHub Packages, not npmjs.com. GitHub Packages needs a GitHub token with read:packages to install, even for public packages: add //npm.pkg.github.com/:_authToken=${GITHUB_TOKEN} to .npmrc or run npm login --registry=https://npm.pkg.github.com.
$ npx gpc-warden dist --base-url https://acme.examplegpc-warden — https://acme.example2 page(s); 2 sale/share vendor(s); GPC handling not found HIGH Sale/share vendors (Meta Pixel, LinkedIn Insight Tag) are used but no code checks navigator.globalPrivacyControl or Sec-GPC [gpc-not-detected] ↳ fix: Read navigator.globalPrivacyControl (and the Sec-GPC request header server-side) and treat it as an opt-out of sale/sharing (CCPA/CPRA, Colorado, Connecticut).HIGH index.html:1 Meta Pixel (script) loads unconditionally on / [gpc-tracker-not-suppressed] ↳ fix: Load it from a script that first checks navigator.globalPrivacyControl (and consent), or tag it for your CMP so it is suppressed when GPC is on.HIGH index.html:1 LinkedIn Insight Tag (pixel) loads unconditionally on / [gpc-tracker-not-suppressed] ↳ fix: Load it from a script that first checks navigator.globalPrivacyControl (and consent), or tag it for your CMP so it is suppressed when GPC is on.MEDIUM .well-known/gpc.json /.well-known/gpc.json: "gpc" must be true or false [gpc-wellknown-invalid]
Why it exists
Global Privacy Control (“Sec-GPC: 1” and navigator.globalPrivacyControl) is a legally binding opt-out of sale and sharing under the CCPA/CPRA and in Colorado, Connecticut and other US states, and California has fined companies for ignoring it. Honouring it means two things: some code has to read the signal, and advertising tags must load in a way that lets that code stop them. gpc-warden checks both in your built site, plus the /.well-known/gpc.json declaration and your privacy policy, and reports each gap with a concrete fix.
CLI, library and GitHub Action. Node.js 18+, zero runtime dependencies. Works on any static build output (Astro, Next.js “output: 'export'”, Eleventy, Hugo, Jekyll, Docusaurus, VitePress, plain HTML) and runs offline: point it at the folder your build writes. By Louis Wright.
Features
Suppression
advertising vendors that sell or share data (Meta, Google Ads, TikTok, LinkedIn, X, Pinterest, Snap, Microsoft, Criteo, Taboola, AddThis, ...) must not load unconditionally: they need a GPC-aware loader or CMP tagging (type="text/plain" + category).
CMPs
OneTrust, Osano, Usercentrics, Didomi, Termly, Ketch, TrustArc, Transcend can honour GPC; confirm it is enabled with --cmp-honours-gpc.
/.well-known/gpc.json
present, valid ({"gpc": true, "lastUpdate": "YYYY-MM-DD"}) and not false while selling/sharing.
Disclosure
the privacy policy mentions GPC / opt-out preference signals.
Usage
# Example
npx gpc-warden dist# Example
npx gpc-warden dist --fail-on medium# Example
npx gpc-warden public --cmp-honours-gpc# Example
npx gpc-warden out --format sarif > gpc.sarifCI / GitHub Action
permissions:
contents: read
security-events: write # only needed for the SARIF upload
jobs:
gpc-warden:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
with: { persist-credentials: false }
- run: npm ci && npm run build # produce the static site first
- uses: MrLouisWright/gpc-warden@v1
with:
path: dist
fail-on: high
sarif: gpc-warden.sarif
- uses: github/codeql-action/upload-sarif@v3
if: always()
with: { sarif_file: gpc-warden.sarif }Options & flags
| Flag | Description |
|---|---|
| Site | |
--base-url <url> | Public URL of the site, e.g. https://example.com (default: inferred from canonical/og:url) |
--include <globs> | Only check these pages (file or URL path globs, comma-separated) |
--exclude <globs> | Skip these pages |
--clean-urls | Pages are served without .html (about.html -> /about) |
| GPC | |
--cmp-honours-gpc | Your CMP (OneTrust, Osano, Usercentrics, ...) is configured to honour GPC |
| Common | |
-c, --config <file> | JSON config (default: .gpc-warden.json or "gpcWarden" in package.json) |
-f, --format <fmt> | text (default) | json | sarif | markdown |
--json <file> | Also write a JSON report |
--sarif <file> | Also write SARIF 2.1.0 |
--markdown <file> | Also write Markdown (e.g. for a job summary) |
--fail-on <sev> | critical | high | medium | low | info | none (default: high) |
--list-rules | Print rules and default severities |
--no-fixes | Hide fix suggestions in text output |
--no-color | Disable colours |
Full reference, config file format and API in the README.
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