Self-hosted transactional email by Omni

Transactional email,
always in flight

Herald is Omni's self-hosted transactional email platform: a send API, delivery tracking, suppression management, and deliverability recommendations.

DKIM-signed
SPF + DMARC aligned
Self-hosted
Open source

POST /messages

curl -X POST https://api.herald.omni.dev/messages \
  -H "Authorization: Bearer hk_live_…" \
  -d '{
    "to": "crew@example.com",
    "from": "team@send.omni.dev",
    "subject": "You're cleared for takeoff",
    "html": "<h1>Welcome aboard</h1>"
  }'

Everything you need to ship email

A focused platform for the email that has to arrive: receipts, verifications, alerts, and everything your product sends.

Transactional send API

A single idempotent endpoint. Verified sending domains, DKIM signing, and suppression checks happen before a message ever leaves.

Delivery tracking

Every message and its lifecycle (delivered, bounced, complained) in one searchable log, updated from real provider webhooks.

Deliverability recommendations

Per-domain guidance on verification gaps, bounce and complaint rates, warm-up, and custom tracking subdomains.

Suppression management

Hard bounces and complaints suppress automatically, so you never re-send into an address that hurts your reputation.

Your own domains

Send from domains you control with SPF, DKIM, and DMARC aligned. Self-hosted means your sending reputation is yours.

Events everywhere

Delivery events stream out as CloudEvents, so the rest of your stack reacts to what happens after send.

Deliverability, built in

Land in the inbox, not the spam folder

Herald watches each sending domain and turns its health into plain, actionable advice, the way a mature email platform should. Verify records, warm up new domains, and keep bounce and complaint rates under control before they cost you the inbox.

Warm up your sending volume

send.omni.dev is still warming up. Keep increasing daily volume gradually so mailbox providers build trust in your mail.

Domain verified

DKIM, SPF, and DMARC all align. You're cleared to send.

Transactional email,always in flight