The offline vault for your
passwords & API keys
Kosh keeps every password, API key, token, login, note, and secret file in one encrypted database on your machine — no cloud, no account, no network by design. Your secrets never leave your machine, and nothing on it can ask for them except you.
कोश — Sanskrit for the treasury that safeguards what's valuable.
Why Kosh
A single desktop app that does one thing well: protect the credentials that live on your laptop.
Envelope encryption
An Argon2id-derived key-encryption-key wraps a random data-encryption-key; every value is sealed with XChaCha20-Poly1305 AEAD. Nothing is stored in plaintext.
Air-sealed
No cloud, no login server, no telemetry, no listener. A build-time guard rejects networking imports in Kosh's own code, so the offline guarantee can't silently regress.
Tamper-evident audit log
Every action is a hash-chained, HMAC-authenticated record. Editing, deleting, or truncating entries is detectable even with full write access to the file.
Typed items
API keys, logins, key pairs, secure notes, and encrypted secret files. Every sensitive field lives only inside the encrypted blob — never a queryable column.
Names without values
Browse which secrets you have without decrypting any value. Decryption happens only on an explicit, audited reveal.
Credential health
Flags expired, expiring-soon, unused, stale, and duplicate credentials so you actually rotate them.
Security you can verify
Kosh implements well-reviewed primitives — and every claim is checkable in the open-source repository.
Argon2id key derivation
Memory-hard, per-vault random salt, cost calibrated to your machine at setup and raisable later.
XChaCha20-Poly1305
Authenticated encryption; each value binds its row id + provider + environment as associated data.
No exfiltration surface
No CLI, no local server, no API, no extension. The only interface is the app's own UI.
Auto-lock in the core
The in-memory key is wiped on idle by the Go backend itself, not just a UI timer.
Screen-capture exclusion
The window is excluded from screenshots and recorders on Windows and macOS.
Portable encrypted backups
Authenticated, self-contained archives you can restore onto a fresh machine.
Honest by policy: Kosh is not "military grade" and not "SOC 2 certified" — certification is an organizational audit, not a property of software. See the threat model in the repository.
Why not just…
Kosh isn't a cloud platform. It's the vault for the keys that live on your laptop.
| Property | .env / spreadsheets | Cloud managers | HashiCorp Vault | Kosh |
|---|---|---|---|---|
| Works fully offline | ✔ | — | — | ✔ |
| No account / no server to run | ✔ | — | — | ✔ |
| Encrypted at rest | — | ✔ | ✔ | ✔ |
| Per-secret, audited access | — | ~ | ✔ | ✔ |
| Tamper-evident log | — | ~ | ✔ | ✔ |
| No queryable API to exfiltrate through | — | — | — | ✔ |
| Zero network by design | ✔ | — | — | ✔ |
| Desktop UX for humans | — | ✔ | — | ✔ |
Need team sharing, mobile sync, or browser autofill? Use 1Password or Bitwarden — Kosh does none of those, by design. Different problems.
Frequently asked questions
Is Kosh free and open source?
Yes. Kosh is 100% free under the Apache-2.0 licence — the same licence covers the source and the official binaries, with no paid tier, no account, and no telemetry.
Does Kosh work completely offline?
Yes — it's air-sealed. Kosh makes zero network connections, and a build-time test fails the build if any first-party package so much as imports a networking library.
What is the best offline secrets manager for API keys?
Kosh is purpose-built for exactly this: an offline, local-first vault for API keys, tokens, key pairs, logins, secure notes, and secret files — encrypted with Argon2id + XChaCha20-Poly1305 and readable only through the app's own UI, one audited reveal at a time.
Is Kosh an alternative to 1Password, Bitwarden, or HashiCorp Vault?
For a specific job, yes. Kosh is the choice when you need no account, no cloud, a provable air-gap, and a tamper-evident local reveal history for keys that should live only on your laptop. It does not do team sync, mobile apps, or browser autofill.
How does Kosh encrypt my secrets?
Envelope encryption: your master password derives a Key-Encryption-Key with Argon2id (memory-hard), which wraps a random Data-Encryption-Key that seals every value with XChaCha20-Poly1305 AEAD. Nothing is stored in plaintext.
Which platforms does Kosh support?
Windows 10/11, macOS, and Linux (Debian/Ubuntu .deb plus a portable binary) — one identical, cross-platform desktop app.
Where does Kosh store my data?
In a single encrypted vault.db in your OS user-data directory — never in the cloud and never inside the install folder, so upgrades never touch your secrets.
Get Kosh
Free, open source, and ready for Windows, macOS, and Linux.