Koltrix
Email API
Retry policies for outbound mail: backoff and give-up times
How long should a sender keep retrying a deferred message? Exponential backoff with jitter, sensible give-up windows and what to tell users meanwhile.
4 min read
Email APIRate limits for email APIs: handling 429s gracefully
Respect Retry-After, smooth bursts with a token bucket and keep retries idempotent. A practical guide to living within an email API's rate limits.
4 min read
Email APIIdempotency keys for email: preventing duplicate sends
A client retry after a timeout should never email a customer twice. How idempotency keys work, the race people miss and how to pick key values.
4 min read