PRACTICAL FIELD GUIDE
Check signature length before a timing-safe comparison
A timing-safe comparison routine may require equal-length inputs. Validate the incoming signature format and length so malformed requests are rejected rather than causing an unhandled exception.
MCPBackend editorial team · · Examples are illustrative
Put it into practice
- Check the expected signature prefix and hexadecimal format.
- Construct the expected signature from the raw body and secret.
- Reject incompatible buffer lengths before calling the constant-time comparison, then handle failure consistently.
What this looks like
ILLUSTRATIVE EXAMPLE
A request has a missing or shortened signature header. Passing it straight to a comparison routine can throw instead of returning false.
A boundary to keep clear
A format check alone is not signature verification. The HMAC must still match the received body.
MCPBackend context
MCPBackend webhooks currently make one delivery attempt with a five-second timeout and no retry or ordering guarantee. Treat them as change notifications, not a durable event ledger. For workflows that must complete, use a durable processing system you operate and reconcile its state against the data API.
Take the next step
Inspect the current project contract, try the change with disposable data, and verify the result through the same credentials your app will use. Record the expected response and one denied-access case before release.
Sources and further reading
These references explain the underlying protocols and design principles. For supported MCPBackend operations and exact request shapes, inspect your project’s generated API contract.