Koltrix
Email API
Modeling email events in your database
Store email delivery events in an append-only table, derive message status from it, and keep the history you need to answer support questions.
5 min read
Email APIProcessing bounce and complaint webhooks end to end
Turn bounce and complaint events into suppressions, user-facing flags and alerts. A worked pipeline from webhook receipt to updated account state.
5 min read
ProductMeasuring Lifecycle Emails With Koltrix Delivery Events
How to use Koltrix webhooks and message events to measure onboarding, trial and dunning emails by what users do next, not by open rates you can't trust.
5 min read
ProductWhat happens after POST /api/v2/emails returns 202
Follow a Koltrix send from the 202 Accepted response through the queue, DKIM signing, SMTP delivery and the webhook events your app receives.
6 min read
Email APIVerifying webhook signatures with HMAC: a practical guide
Never trust a webhook until you verify its signature over the raw body. HMAC verification in Node, Python and Go, plus timestamp and replay checks.
5 min read
Email APIBuilding webhook consumers for retries and disorder
Webhooks arrive late, twice or out of order. Design consumers that acknowledge fast, deduplicate by event, process asynchronously and tolerate disorder.
4 min read