Works with your tools. No surprises.
OtterStorage is 100% compatible with the Amazon S3 API, including S3 Object Lock for WORM immutability in Governance mode and Compliance mode. If your backup software speaks S3, it works with us — just change the endpoint.
Compatibility matrix
Backup and NAS solutions verified against S3-compatible storage with Object Lock. Immutability is enforced at the bucket level; the column shows whether the application is able to manage it (enable the lock and honour the retention).
| Solution | S3 compatible | Immutability (Object Lock) |
Governance mode | Compliance mode | Minimum version / notes |
|---|---|---|---|---|---|
| Veeam Backup & Replication | v12. Compliance since v10; Governance since v12.1. | ||||
| Commvault | v11.20+. WORM Storage Lock enables compliance lock. | ||||
| QNAP — HBS 3 | HBS 3 18.0.1012+. Mode is chosen when creating the bucket. | ||||
| Synology — Hyper Backup | 1 | bucket | bucket | Backs up to Object-Lock buckets via “S3 Storage”. |
1 Synology Hyper Backup can write to Object-Lock buckets (WORM immutability is honoured at the bucket level), but the application does not rotate or delete locked versions once retention expires, so backup size may grow steadily. Plan your bucket retention accordingly.
Governance mode vs. Compliance mode
S3 Object Lock protects your objects with a WORM model (write once, read many). There are two retention modes, and OtterStorage supports both.
Governance mode
Objects cannot be deleted or overwritten during the retention period, except by users holding the special s3:BypassGovernanceRetention permission. It allows correcting mistakes or shortening/extending retention in a controlled way.
Best for:
- • Operational protection against accidental deletion or ransomware.
- • Environments where administrators need an escape hatch.
Compliance mode
Objects cannot be deleted or modified by anyone — not even the root account or OtterStorage — until retention expires. The lock is absolute and irrevocable.
Best for:
- • Regulatory requirements: SEC 17a-4, FINRA, DORA, GDPR.
- • “Ransomware-proof” backups that must survive an attacker with admin credentials.
Not using any of these?
Because it is S3-API compatible, any tool, SDK or CLI that speaks S3 works with OtterStorage with no changes. Immutability is available via Object Lock in every case.
Indicative matrix based on each vendor's public documentation (June 2026). Minimum versions and immutability behaviour may change; always verify compatibility against the provider's official documentation. More on security and immutability →
Your tool isn't on the list?
If it speaks S3, it almost certainly works. Tell us your case and we'll validate it with you.