Write or check
--write adds integrity (and crossorigin) attributes; --check fails on missing, wrong or stale values.
npm package · MIT · Node ≥ 18
sri-sentinel
Subresource Integrity for your built site: generate, write and check it in CI.
Scans the HTML in your build for scripts, stylesheets, modulepreload / preload links and import map entries, hashes the local files (and CDN files with --remote), then either writes integrity and crossorigin attributes or checks the existing ones are correct. Vite, webpack, Rollup, esbuild and Astro integrations. Zero runtime dependencies.
npm i -D sri-sentinel
$ npx sri-sentinel dist --checkdist/index.html 4: high <link> "/assets/app.css?v=42" has no integrity attribute [missing-integrity] ↳ Add integrity="sha384-IBXuE+SKr6nOANxq1LIznMbjQUHDJ3PY6mUpF3ZQCTz1+rK8Fip9GAGqRq59yH3C" 5: high <script> "https://cdn.jsdelivr.net/npm/htmx.org@2.0.3/dist/htmx.min.js" has no integrity attribute [missing-integrity] ↳ Run with --remote to fetch and hash it, then --write 6: critical Integrity for "./assets/app.js" does not match its content (wrong or stale) [integrity-mismatch] 7: medium Could not resolve "/assets/vendor.js" (file not found: dist/assets/vendor.js) [unresolved-resource] ↳ Check the path and --base, or allowlist it 1 HTML file(s), 4 resource(s): 1 critical, 2 high, 1 medium
The problem
If a CDN or asset host is compromised, anything you load from it runs with full access to your page. Subresource Integrity stops that, but hand-maintained hashes go stale on every rebuild and a single missing crossorigin attribute makes the browser block the file.
sri-sentinel writes the hashes for you after each build and fails CI when one is missing, wrong or stale.
Features
CDN resources
--remote fetches and hashes cross-origin files too.
Import maps
Fills the integrity object inside <script type="importmap">.
Lazy chunks
The webpack plugin patches the webpack 5 runtime so import() chunks get integrity too.
Browser-accurate checks
Only the strongest algorithm counts, any hash of it may match; base64url and ?options accepted.
Build integrations
Vite, webpack, Rollup, esbuild and Astro.
Allowlists that expire
Per-rule or per-URL exemptions with a reason and an expiry date.
Manifests & reports
JSON manifest of resource → integrity; text, JSON, SARIF and Markdown reports.
Usage
# Add integrity attributes
npx sri-sentinel dist --write# Fail CI on bad integrity
npx sri-sentinel dist --check# Include CDN resources
npx sri-sentinel dist --write --remote# Write a manifest
npx sri-sentinel dist --manifest sri.jsonCI / GitHub Action
name: SRI
on: [push, pull_request]
jobs:
sri:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- uses: actions/setup-node@v4
with: { node-version: 20 }
- run: npm ci && npm run build
- uses: MrLouisWright/sri-sentinel@v1
with:
paths: dist
mode: check # or write
remote: 'true'
fail-on: high
sarif: sri.sarifOptions & flags
| Flag | Description |
|---|---|
--check | Report missing, wrong or stale integrity (default) |
--write | Write integrity (and crossorigin) attributes into the HTML |
-a, --algorithm <alg> | sha256 | sha384 | sha512 (default: sha384) |
--remote | Fetch and hash remote (CDN) resources |
--base <path> | Public base path, e.g. /app/ (default: /) |
--origin <url> | Site origin; absolute URLs on it are treated as local files |
--crossorigin <v> | anonymous | use-credentials (default: anonymous) |
--manifest <file> | Write a JSON manifest of resource -> integrity |
--config <file> | Config file (default: .sri-sentinel.json or package.json "sri-sentinel") |
--fail-on <sev> | critical | high | medium | low | info | none (default: high) |
--format <fmt> | text | json | sarif | markdown (default: text) |
--json/--sarif/--markdown <file> | Also write that report to a file |
--timeout <ms> | Remote fetch timeout (default: 10000) |
-q, --quiet | Only print the summary |
Full reference, config file format and API in the README.
Support this project
Support open-source security tools
I build free, open-source tools that help developers ship safer websites. Every coffee helps keep them maintained, documented and free for everyone.
Buy me a coffee (opens Stripe in a new tab)Secure checkout by Stripe
More tools by Louis Wright
58 tools
Flagship Next.js 16 App Router libraries · pre-alpha · 2
- next-tonguePre-alphaCompiler-first, type-safe i18n for the Next.js 16 App Router.ICU messages compiled at build time, works with TurbopackLocale from route params, so pages stay in the static shellZero dependencies beyond next and react
- next-heraldPre-alphaTyped metadata, safe JSON-LD, sitemaps and an SEO CI check for the Next.js 16 App Router.Returns native Metadata, Sitemap and Robots objectsXSS-safe JSON-LD with an entity graph by defaultherald check: a dependency-free CI crawler for SEO mistakes
Sentinels security scanners & CI gates · 19
- binary-sentinelStatic PE and ELF triage in pure JavaScript: headers, sections, entropy, imports, imphash, packer hints, capabilities and hardening checks.
- cookie-sentinelAudit the cookies your site sets before attackers do.
- defang-sentinelDefang and refang indicators of compromise, and stop live malicious links from getting into threat reports, tickets and docs.
- dns-sentinelAudit your domains' DNS and email security before attackers or spammers find the gaps.
- dockerfile-sentinelSecurity linter for Dockerfiles and Docker Compose files: root containers, baked-in secrets, curl | sh, unpinned and end-of-life base images, privileged services, Docker socket mounts and exposed databases.
- dotenv-sentinelValidate .env files against .env.example or a schema, catch weak and default secrets, and keep .env files out of git, including its history.
- hash-sentinelCheck file hashes against your own threat feeds, MISP and optional public lookups, offline-first.
- header-sentinelFail CI when deployed URLs ship weak HTTP security headers.
- ioc-sentinelExtract indicators of compromise from threat reports, logs, emails and binaries, then export them as CSV, STIX 2.1, JSON or SARIF.
- license-sentinelA license compliance gate for npm projects, plus CycloneDX/SPDX SBOMs and a NOTICES file.
- malware-report-sentinelTurn a suspicious file into a structured malware triage report (Markdown, HTML or JSON) using static analysis only.
- phish-sentinelOffline phishing URL heuristics with an explainable score: lookalike and homograph domains, brand impersonation, IP hosts, user@host tricks, risky TLDs, shorteners, free hosting and redirect chains.
- redirect-sentinelFind open redirects and mixed content in a built site (offline) or a live crawl: http:// scripts and styles on HTTPS pages, insecure forms, client-side redirects fed by the URL, open redirect rules in _redirects/vercel.json/nginx, HTTPS downgrades, and optional safe redirect probing.
- sbom-diff-sentinelSee exactly what a pull request changes in your software bill of materials, and block the risky changes.
- securitytxt-sentinelValidate security.txt (RFC 9116) and robots.txt for your domains, or as local files in CI before you deploy them.
- static-link-sentinelFail CI on broken links before you deploy.
- supply-chain-sentinelOne supply-chain gate for npm projects: risky dependency changes, license policy, new vulnerabilities and SBOM drift, and GitHub Actions hardening, with one config, one report and one exit code.
- tls-sentinelCheck TLS endpoints for expiring or untrusted certificates, hostname mismatches, missing intermediates, weak keys and signatures, TLS 1.0/1.1, weak ciphers and missing TLS 1.3.
- workflow-sentinelCatch insecure GitHub Actions workflows before they're merged.
Gauges package & repo quality · 8
- commit-gaugeA lightweight Conventional Commits linter for git hooks and CI, with clear fix-up suggestions.
- dead-deps-gaugeFind dependencies you declare but never use, and imports that are missing from package.json.
- engines-gaugeMake engines.node, your CI matrix, .nvmrc and your dependencies' engine requirements agree.
- monorepo-gaugeHygiene checks for npm, yarn and pnpm workspaces: circular internal deps, mismatched shared deps, version drift and missing fields.
- pkg-field-gaugeValidate package.json before you publish: exports/main/types consistency, files, repository, keywords and sideEffects.
- publish-gaugeCheck what npm publish will actually ship, before you publish it.
- readme-gaugeLint READMEs for missing sections, broken badges, stale install commands and missing usage examples.
- semver-gaugeA CI gate that checks your version bump matches what changed, and that the CHANGELOG has a real entry for it.
Beacons SEO & discoverability · 9
- answer-beaconCheck that your built static site is ready for answer engines and AI search: direct answers, FAQ schema, llms.txt, AI crawler access and E-E-A-T signals.
- canonical-beaconCheck canonical tags and hreflang clusters in your built static site: one canonical per page, pointing at a real, indexable, final URL, and hreflang clusters that are valid, self-referencing and reciprocal.
- duplicate-beaconDetect duplicate and near-duplicate titles, meta descriptions and page bodies across your built static site.
- heading-beaconAudit the heading structure of your built static site: one visible H1 per page, a logical H1 → H2 → H3 outline, and headings that actually say something.
- index-beaconCheck which pages of your built static site search engines are told not to index or follow, via meta robots and X-Robots-Tag, against the rules you actually intend.
- meta-beaconAudit titles, meta descriptions, Open Graph and Twitter/X cards across a built static site.
- orphan-beaconFind the pages in your built static site that nothing links to, and measure how many clicks every page is from the homepage.
- schema-beaconValidate JSON-LD and microdata against schema.org and Google rich-result requirements, across your whole built site.
- sitemap-beaconAudit XML sitemaps against your built static site: every URL should be a real, indexable, canonical page, and every such page should be listed.
Wardens privacy, compliance & accessibility · 8
- a11y-wardenWCAG 2.2 accessibility audit of static HTML for CI, with a baseline so you can adopt it on an existing site and only fail on new problems.
- consent-wardenCheck that your cookie banner actually behaves: nothing non-essential loads before opt-in, Reject is as easy as Accept, and consent can be withdrawn.
- dsar-wardenAssemble Data Subject Access Request exports from many systems into one structured, checksummed bundle, and catch the mistakes before you send it.
- gpc-wardenCheck that your built site honours Global Privacy Control: it reads the signal and suppresses sale/share trackers when it is on.
- pii-log-wardenFind and redact personal data in log files: emails, phone numbers, IP addresses, card numbers and national IDs.
- policy-drift-wardenCompare the trackers and third parties your built site actually loads with what its privacy policy says, and fail CI when they drift apart.
- retention-wardenLint your data-retention policy as code: every data category gets a period, a legal basis and an action at expiry.
- tracker-wardenInventory every third-party tracker, pixel and SDK your built static site loads, with vendor, company and category, and gate CI on an approved-vendor list.
Pulses web performance · 8
- bundle-pulseA CI gate for JavaScript and CSS bundle size: budgets on raw, gzip and brotli sizes, and a diff against your base branch.
- cache-pulseCheck that your static hosting config caches the right things: fingerprinted assets for a year, HTML revalidated, and nothing stale after a deploy.
- font-pulseAudit how your built site loads web fonts: font-display, preloads, WOFF2, subsetting, unused weights and total font payload.
- image-pulseFind oversized, unoptimised and wrongly formatted images in your built site, before they slow down your Largest Contentful Paint.
- lazy-pulseLazy-load what is below the fold, never the LCP image: a static lazy-loading audit for your built site.
- render-pulseFind the CSS and JavaScript that block first paint in your built site, with the defer, async, media or critical-CSS fix for each.
- thirdparty-pulseHow much does each third-party script cost your pages? Estimated bytes, requests and main-thread time per page and per vendor, checked against budgets.
- vitals-pulseFail CI when Core Web Vitals get worse: LCP, CLS and an INP proxy, gated on thresholds and on regressions against your baseline.