Developer guide: idempotent requests

Short answer: Every POST needs an Idempotency-Key header (16 to 80 letters, digits, - or _), one per intended action. The same key with the same body returns the same answer (idempotency-replayed: true); the same key with another body is refused with 422 idempotency_key_reused. Writes are also recognised by externalId next time, so a retry never duplicates a record.

Verified for PVology 0.61.0 · updated 2026-10-11