Tarsnap is the gold standard for zero-knowledge Unix backups — open-source client, independently auditable, designed by a respected cryptographer. We share those values. Where we differ is in the operations layer: databases, dashboards, verified restores, and team access.
Tarsnap is genuinely excellent at what it does. Its cryptography is open-source and independently auditable. Its creator, Dr. Colin Percival, is a respected security researcher. For a single Unix box with small, slowly-changing data, pay-per-use pricing ($0.25/GB-month on deduplicated data) can cost less than a dollar a month. If you enjoy owning your backup scripts and trust the CLI above all else, Tarsnap is a reasonable choice and this page won't try to argue you out of it.
Tarsnap's pay-per-use can be cheaper for small, slowly-changing datasets. For active SaaS databases, the cost grows with backup frequency and dataset size. Calm Backup's flat pricing is predictable regardless of churn rate.
| Tarsnap | Calm Backup | |
|---|---|---|
| Zero-knowledge encryption | ✓ AES-256 · open-source client | ✓ AES-256-GCM · key never leaves you |
| Encryption model | User-held key · auditable code | User-held key · turnkey setup |
| Open-source client | ✓ | — |
| Native Postgres backup | — (you script pg_dump) | ✓ Auto-detected |
| Native MySQL backup | — (you script mysqldump) | ✓ Auto-detected |
| Native MongoDB backup | — (you script mongodump) | ✓ Auto-detected |
| Automated restore verification | — | ✓ Daily sandbox-tested |
| Web dashboard | — | ✓ |
| Weekly digest email | — | ✓ |
| Team access / roles | — | ✓ (Scale plan) |
| SOC 2 evidence / audit export | — | ✓ (Scale plan) |
| Pricing model | $0.25/GB-mo · pay per use | $5/$15/$95+ flat /mo |
| CLI | ✓ (primary interface) | ✓ Single binary |
| Windows support | — | — |
| Platform | Linux, BSD, macOS only | Linux, macOS, Docker |
pg_dump to disk first, then Tarsnap archives the dump file. You write and maintain that pipeline. Calm Backup auto-detects Postgres, MySQL, and MongoDB — no scripting required. Both Tarsnap and Calm Backup are zero-knowledge: your data is encrypted with a key that never leaves your machine, and neither vendor can read your backup data. Both use strong symmetric encryption (Tarsnap: AES-256; Calm Backup: AES-256-GCM). The pitch for Calm Backup is not that we're more secure — it's that we've built the operations layer you'd otherwise build yourself: database auto-detection, restore testing, a dashboard, email reports. Tarsnap's trust model, with the tooling a small SaaS team actually needs.
Calm Backup offers a 14-day free trial on all plans with no credit card required. Tarsnap has no trial — you prepay credits and are charged for actual usage, which can work out to very little for small datasets. The honest answer is that if your Tarsnap bill is under $2/month, our $5/mo Solo plan is not cheaper. If it's above $5/mo or you need database support, the comparison becomes more interesting.
Calm Backup has native Postgres backup support — it auto-detects your Postgres instances and handles the dump automatically. Tarsnap itself has no database support; you'd need to run pg_dump separately and point Tarsnap at the resulting file. The Tarsnap approach works, but the scripting and scheduling are your responsibility.
Both are zero-knowledge: your data is encrypted with a key that neither vendor can access. Tarsnap's open-source client gives you the ability to audit the cryptography directly, which is a meaningful advantage we can't replicate. Our encryption (AES-256-GCM) is strong and industry-standard, but our client is not open-source. If auditability of the backup client itself is your primary security requirement, Tarsnap is the stronger choice on that specific axis.
Your data is permanently gone — that is intentional by design. Calm Backup uses the same zero-knowledge model: your key is generated locally and never leaves your machine, so Calm Backup cannot recover it for you either. On both tools, you must safeguard your key yourself (for example, in a password manager or secrets vault). The difference is ergonomics: Calm Backup's setup is turnkey rather than requiring you to manage a key file manually from the start.
No — Tarsnap is Unix-only (Linux, BSD, macOS). Calm Backup is also Unix-focused: Linux and macOS as primary platforms, with Docker support. Neither tool is the right choice if Windows is a primary target.
Yes. They operate independently. Some teams keep Tarsnap for system-level file archives (where its deduplication and pay-per-use pricing are most efficient) and use Calm Backup for databases and shared team visibility. There's no conflict.
Native Postgres, MySQL, and MongoDB. Verified restores daily. Dashboard and weekly reports. 14-day free trial, no credit card.
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