Klef

Personal, zero-knowledge .env sync. Paste your env files in, sync them across machines, pull them back down — all end-to-end encrypted. The server only ever stores ciphertext; your keys never leave the browser.

Live at klef.sh — free, open source (AGPL-3.0), and built to be self-hosted on your own Cloudflare account.

What it does

• Paste → diff → save. Paste an updated env file, review a line-level diff against the stored version (computed client-side, on decrypted text the server never sees), confirm, done.
• End-to-end encrypted. AES-256-GCM in the browser, before upload. The server, and the operator, can't read your values — ever.
• Version history + restore. Every save is a new immutable version.
• Sign in ≠ unlock. Google OAuth or passkeys prove who you are; a separate master passphrase (never sent anywhere) decrypts your data. Lock the vault — manually, by shortcut, or on an inactivity timer — without signing out.
• Recovery key. A one-time KLEF-XXXXX-… code is your only fallback if you forget the passphrase. Lose both and the data is unrecoverable by design.
• Organize by workspace → project → file, with environment labels (development/staging/production) and per-framework file-name suggestions.

Who it's for

Klef is deliberately not an Infisical/Doppler/Vault competitor. No CLI, no daemon, no file watcher, no team RBAC — just a dead-simple, truly zero-knowledge vault for the .env files you'd otherwise sync through AirDrop, Slack DMs, or a gist. If you need machine-to-machine secrets injection, use one of those tools; if you're one developer with several machines and a pile of env files, Klef is the honest, minimal answer.

How it works (threat model in brief)

• Zero-knowledge. Env contents are encrypted in your browser with AES-256-GCM under a random per-account data-encryption key (DEK). The DEK is wrapped by a key derived from your master passphrase — Argon2id (19 MiB, t=2, per-account salt), with a PBKDF2-SHA-256 (600k) fallback where WASM is unavailable. The server sees only ciphertext, salts, and nonces.
• Names plaintext, values encrypted. Workspace/project/file names are stored in plaintext for navigation; only env contents are encrypted.
• Auth ≠ unlock. Logging in (Google/passkey) gets you a session; a separate master passphrase decrypts your data. A logged-in but locked client sees only ciphertext.
• No server-side recovery. Lose both your passphrase and your recovery key and the data is gone — by design. There is no reset Klef could perform, because Klef never has the keys.

The full cryptographic contract lives in src/shared/BLOB_FORMAT.md, the parameters in src/shared/constants.ts, and a prose walkthrough at klef.sh/security.

Klef does not protect against a compromised client device (keylogger, malicious extension), a weak passphrase brute-forced offline, or loss of both passphrase and recovery key.

Stack

Vite + React SPA (owns all crypto/diffing) · Hono on Cloudflare Workers · Better Auth · Cloudflare D1 · Wrangler + @cloudflare/vite-plugin. One package, one dev server running the SPA and the Worker against real workerd with a real D1 binding. No analytics, no trackers, no third-party scripts.

Develop

Requires Node 20+ and pnpm.

pnpm install
cp .dev.vars.example .dev.vars        # auth secrets for local dev
pnpm db:migrate:local                 # apply migrations to local D1
pnpm dev                              # http://localhost:5173

Other scripts:

pnpm test          # Vitest: crypto units (node) + Worker/D1 (workerd via Miniflare)
pnpm typecheck     # tsc --noEmit
pnpm build         # typecheck + production build + prerendered marketing pages

Self-hosting

Klef is built to be forked and self-hosted on your own Cloudflare account — the single-repo Cloudflare deploy makes this genuinely easy, and it's a first-class use case.

# 1. Fork + clone, then install
pnpm install

# 2. Authenticate Wrangler with your Cloudflare account
pnpm exec wrangler login

# 3. Create your own D1 database, then put its id in wrangler.jsonc
pnpm exec wrangler d1 create klef-db   # copy the database_id into wrangler.jsonc

# 4. Apply the schema to your remote D1
pnpm db:migrate:remote

# 5. Set production secrets (never committed)
pnpm exec wrangler secret put BETTER_AUTH_SECRET   # openssl rand -base64 32
pnpm exec wrangler secret put BETTER_AUTH_URL      # https://your-domain
pnpm exec wrangler secret put GOOGLE_CLIENT_ID
pnpm exec wrangler secret put GOOGLE_CLIENT_SECRET

# 6. Ship it
pnpm deploy

Create the Google OAuth client at the Google Cloud Console with an authorized redirect URI of https://your-domain/api/auth/callback/google.

Because everything is end-to-end encrypted, the operator (you) still can't read any stored secret — the same zero-knowledge guarantee holds whether Klef is hosted by its author or by you.

FAQ

Why not just use Doppler/Infisical? They're great team products with server-side secret access for machines and CI. Klef trades all of that away for one property they can't offer in their hosted form: the server mathematically cannot read your secrets.

What happens if klef.sh disappears? Export your files anytime, or self-host — the code is AGPL and the deploy is one wrangler command.

Can I trust the client code? The same question applies to any E2EE web app. Klef's mitigation is radical transparency: the entire codebase is open, the crypto is isolated in small pure functions (src/shared/), and you can self-host to pin the code you audited.

Contributing

Contributions are welcome — please read CONTRIBUTING.md first. It covers the dev workflow, the rule that the zero-knowledge crypto contract must stay intact, how contributions are licensed, and the DCO sign-off (git commit -s) that CI enforces.

Security

See SECURITY.md for the threat model and how to report vulnerabilities.

License

AGPL-3.0-or-later. Open source from the first commit — for a secrets tool, auditability is the whole trust story.