COMPARE
Fern builds your SDKs and MCP server from your OpenAPI spec. StateAnchor gates every spec change to ensure those SDKs never break. The two tools work together — not against each other.
Fern builds your SDK. StateAnchor ensures it never drifts.
CAPABILITIES
Most teams use both. Fern for generation. StateAnchor for enforcement.
SIDE BY SIDE
A factual row-by-row view of what each tool covers. Fern is excellent at generation — this comparison is not dismissive of that. Check buildwithfern.com for the latest on their capabilities.
| Capability | Fern | StateAnchor | Together |
|---|---|---|---|
| SDK generation | ✓ | — | ✓ |
| Contract enforcement | — | ✓ | ✓ |
| MCP server generation | ✓ | ✓ | ✓ |
| Drift detection | — | ✓ | ✓ |
| Git-native gate | — | ✓ | ✓ |
THE CORE DISTINCTION
“Did my spec produce correct SDK and MCP output?”
“Is this spec change safe to ship to consumers?”
Fern handles generation. StateAnchor handles enforcement. Not a replacement — the enforcement layer Fern doesn’t ship.
Already using Fern?
Gate-only mode sits on top of Fern’s SDK generation — same output, with contract enforcement added. StateAnchor gates the spec before Fern runs. Your generated SDKs and MCP servers continue to build from specs that have passed the safety check. No conflict, no duplication.
Fern handles generation. StateAnchor handles enforcement. Not a replacement — the layer Fern doesn’t ship.
Connect a repo in ~=5 minutes. The gate runs on every push automatically.
Free to start. No credit card required.