Provider patterns
AWS, Stripe, GitHub, Slack, OpenAI, Anthropic, Google, Twilio, SendGrid, Mailgun, npm, private keys, database URLs and more.
npm package · MIT · Node ≥ 18
bundle-secret-guard
Fail the build when secrets ship to the browser.
Scans your built frontend (dist/, build/, out/, .next/static), including source maps, for provider keys like AWS, Stripe, GitHub, OpenAI, Anthropic and Supabase service_role, and for any server-only .env value that got inlined. Every finding is redacted and comes with a specific fix.
npm i -D bundle-secret-guard
$ npx bundle-secret-guard -e .env dist/assets/index-DMZFQv-v.js ✖ error Stripe secret/restricted live key [stripe-secret-key] dist/assets/index-DMZFQv-v.js:1:720 sk_l…(36 chars) fix: Rotate the key immediately (Stripe Dashboard → Developers → API keys → Roll key) ✖ error Server-only env value found in bundle [env-leak] Value of STRIPE_SECRET (from .env) appears literally in the bundle. fix: Move the call that needs this key to a server/API route dist/assets/index-DMZFQv-v.js.map ⚠ warn Source map shipped [source-map] fix: Vite: build.sourcemap = false or "hidden" and don't deploy *.map. 3 file(s) scanned: 4 error(s), 1 warning(s)
The problem
One import from the wrong file, or a secret in a VITE_ / NEXT_PUBLIC_ variable, and your Stripe or OpenAI key is sitting in a public JavaScript bundle. Repository secret scanners never see it, because the leak only exists in build output.
bundle-secret-guard scans what you actually deploy, cross-checks it against your .env files, and fails the build before the key goes live.
Features
.env cross-check
Any non-public .env value that appears literally in the bundle is an error; secret-looking public-prefix vars are flagged too.
Source maps scanned
Shipped .map files are flagged and their sourcesContent is scanned as well.
gitleaks rules
Import your existing gitleaks TOML rules with --gitleaks.
Entropy + baseline
Optional high-entropy detection, with a detect-secrets style baseline stored as SHA-256 hashes only.
Opt-in live verification
--verify checks supported tokens against only that provider's own API. Off by default.
Redacted output
Secrets are never printed in full: only the first 4 characters and the length.
Plugins & SARIF
Vite and webpack plugins, JSON and SARIF output, zero runtime dependencies.
Usage
# Scan after building
npx bundle-secret-guard dist# Cross-check .env files
npx bundle-secret-guard dist -e .env -e .env.production# Use gitleaks rules
npx bundle-secret-guard dist --gitleaks .gitleaks.toml# Next.js build script
next build && bundle-secret-guard .next/static -e .env -e .env.productionCI / GitHub Action
# .github/workflows/bundle-secrets.yml
name: Bundle secrets
on: [push, pull_request]
jobs:
scan:
runs-on: ubuntu-latest
permissions: { contents: read, security-events: write }
steps:
- uses: actions/checkout@v4
- uses: actions/setup-node@v4
with: { node-version: 20 }
- run: npm ci && npm run build
- uses: MrLouisWright/bundle-secret-guard@v1
with:
dirs: dist
env-files: .env.production
sarif: bundle-secrets.sarif
- if: always()
uses: github/codeql-action/upload-sarif@v3
with: { sarif_file: bundle-secrets.sarif }Options & flags
| Flag | Description |
|---|---|
[dir...] | Build directories (default: auto-detect dist, build, out, .next/static, .output/public, .svelte-kit/output/client) |
-e, --env-file <file> | .env file to cross-check (repeatable) |
-c, --config <file> | JSON config (default: .envleakrc.json / .bundlesecretguardrc.json / bundle-secret-guard.config.json) |
--fail-on <level> | error | warn | none (default: error) |
--json | Print JSON results |
--sarif [file] | Print SARIF 2.1.0 (or write to file) |
--max-file-size <n> | Skip files bigger than n bytes (default 5mb; accepts 500kb, 10mb) |
--public-prefix <p> | Extra public env prefix (repeatable) |
--gitleaks <file> | gitleaks TOML rules (repeatable) |
--baseline <file> | Baseline JSON (suppress known hashed findings) |
--update-baseline | Write new findings to the baseline (hashes only) |
--entropy-scan | Extra high-entropy string detection |
--verify | Opt-in live-key check via each provider's API (off by default) |
--no-info | Hide info-level findings |
Full reference, config file format and API in the README.
Support this project
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