Sendibl Documentation
Sendibl is a transactional and marketing email API. Verify a domain, grab an API key, and send your first email in a few minutes — with delivery events, webhooks, templates, and broadcasts built in.
Base URL & authentication
Every API request goes to https://api.sendibl.com and authenticates with an API key in the Authorization header:
Authorization: Bearer sb_...
Create keys in the dashboard under API Keys. Keys are shown once at creation and stored hashed.
Send your first email
Until you verify a domain you can still develop against test mode addresses — they simulate the full delivery pipeline without sending real mail:
curl -X POST https://api.sendibl.com/emails \
-H "Authorization: Bearer sb_..." \
-H "Content-Type: application/json" \
-d '{
"from": "Acme <hello@acme.com>",
"to": ["delivered@test.sendibl.com"],
"subject": "Hello from Sendibl",
"html": "<p>It works!</p>"
}'The response is {"id": "eml_..."}. Sends are processed asynchronously — poll GET /emails/:id for the event timeline, or subscribe to webhooks.
To send from your own domain, add it under Domains, publish the DNS records (or let the one-click Cloudflare setup do it), and verify. Production sends from unverified domains are rejected.
Using the Resend SDKs
Sendibl's sending API is shape-compatible with Resend's, and the official Resend SDKs support a base-URL override — so you can use them as-is:
# environment RESEND_API_KEY=sb_... RESEND_BASE_URL=https://api.sendibl.com
# environment RESEND_API_KEY=sb_... RESEND_API_URL=https://api.sendibl.com
Plans & quotas
Free includes 3,000 emails/month, Pro 50,000, and Scale 100,000. When a send would exceed your monthly quota the API returns 429. See pricing for details.