Email infrastructure you can reason about
A sending API and authenticated SMTP relay with verified domains, per-message DKIM signing, and delivery events that report exactly what the receiving server said — never a guess.
Trusted by 2,000+ developers3,000 emails/month free · no card required · verified domains only
$ curl https://api.spaceflare.org/v1/emails \
-H "Authorization: Bearer sf_live_…" \
-H "Content-Type: application/json" \
-d '{
"from": "billing@yourdomain.com",
"to": "customer@example.com",
"subject": "Your invoice",
"html": "<p>Thanks!</p>"
}'
// 202 Accepted — queued, not delivered
{ "id": "5f2c…", "status": "queued" }- SMTP ports
- 587 · 465
- DKIM signing
- RSA-2048
- Queue durability
- Postgres
- Retries
- Exponential
Teamsshipcriticalmailonspaceflare
ScrollX UI aligns with the ecosystem powering the world’s most ambitious products.
Everything needed to send, and nothing hidden
Limits are enforced at send time. Acceptance is not treated as delivery. Quotas, prices and thresholds all come from the database, not from hardcoded copy.
One API for email
POST /v1/emails with HTML, text, attachments, templates, scheduling and idempotency keys.
SMTP that behaves
STARTTLS and implicit TLS, API-key or credential auth, rotating credentials per account.
Real domain verification
SPF, DKIM, DMARC and return-path checked with live DNS. Never marked verified without proof.
Honest delivery data
Per-recipient SMTP transcripts, deferral backoff, bounce and complaint processing.
Deliverability handled with evidence
Every message is DKIM-signed with a per-domain 2048-bit key. Domain verification queries live DNS, return-path and HELO hostnames are configurable, and reputation thresholds pause sending before damage spreads.
- Per-domain DKIM keypairs with rotation
- SPF, DMARC and custom Return-Path records
- MX discovery with caching and per-domain concurrency limits
- Exponential backoff, dead-letter queue, and DSN processing
- Bounce and complaint suppression with automatic restriction
- 202Accepted by API14:02:11.084
- 250Delivered to mx1.example.com14:02:13.902
- DSNHard bounce — mailbox unavailable14:31:07.441
- —Recipient added to suppression list14:31:07.612
Start with 3,000 emails, free
Verify a domain, create a key, and send your first message in minutes. Upgrade when your volume does.