Integrations posts
Everything in the journal filed under integrations.
2026
Payment webhooks: signatures, replays and idempotency keys
Verify the signature over the raw body, reject old timestamps, store the event id, never trust the amount. A compact handler and the checks around it.
Idempotent jobs: doing the work exactly once
Queues and webhooks deliver at least once, so every handler runs twice eventually. How to make the second run harmless with a key and a constraint.
2025
Proxy tunnels that die after ten idle seconds
A tunnel that closes on idle turns one long session into thousands of reconnects. On metered bandwidth the handshake traffic quietly becomes the bill.
Treating a rate limit as a permanent failure is expensive
A 429 or a protocol throttle means come back later. A client that files it as a permanent failure throws away paid work and hides the real capacity.
Mail lands in spam: the From alignment nobody checks
SPF and DKIM can both pass while mail keeps landing in spam. The header that explains it names three domains, and DMARC only accepts one answer.