How webhooks work in plain English
You give Senddio a URL on your servers. Whenever an interesting event happens — a message is delivered, an email is opened, a customer replies — Senddio makes an HTTPS POST to that URL with a JSON body describing the event. Your server receives the request, does whatever it needs to do, and responds with HTTP 200 to confirm receipt.
Why webhooks matter
Webhooks are how modern apps stay in sync. Without them, you would have to poll an API constantly to check for new events, which is slow, wasteful, and easily falls behind real time. With webhooks, the moment something happens, your system knows.
Webhook security
Senddio signs the raw JSON body with HMAC-SHA256 using the endpoint secret. Verify Senddio-Signature before processing. The signed body includes a timestamp; your receiver is responsible for freshness checks and duplicate-safe processing.
Retries and idempotency
Senddio uses five delivery attempts with configured delays of 0, 60, 300, 1800 and 7200 seconds. Delivery IDs identify attempts, not a stable logical event across retries. Make side effects idempotent using message identity, event type and your application’s state.