Authenticate before side effects
Validate the provider signature or equivalent authenticity mechanism before changing payment, order or fulfillment state. Reject malformed or unverifiable payloads.
Make duplicate delivery harmless
Persist a provider event or transaction identifier before applying irreversible side effects. A repeated callback should converge on the same domain state.
receive → authenticate → deduplicate → validate transition → commit → acknowledgeRetry work, not unsafe side effects
Acknowledge only after the durable handoff required by that integration succeeds. Long-running downstream work should move to a queue with bounded retries and a dead-letter path.
Project-specific contracts win.
These pages describe Thonem implementation patterns. Exact endpoints, payloads, credentials, retry rules and provider capabilities must be taken from the deployed project and its provider documentation.