Documentation

Calder is transactional email infrastructure: one endpoint in, delivered events out.

Before you start

  1. An API key. Grab a test key — no DNS homework, nothing real gets delivered. Join the waitlist for yours.
  2. A verified sending domain — or skip it. Test keys work with zero DNS setup; add a real domain under Domains whenever you’re ready to go live.

Quickstart

TSNode.jsfetch in minutes.PYPythonrequests, same shape.GOGonet/http, no deps.PHPPHPcURL extension.RBRubynet/http stdlib.$_cURLRaw HTTP.SHShellScript the API.

Explore

✉EmailsSend and track.✓DomainsVerify and monitor.↯WebhooksEvents, signed.◈API KeysTest vs live.◔Usage & BillingMetered, NGN/USD.