SRS Postline

Email infrastructure for SRS

Transactional email that scales with your stack

REST API and SMTP submission, domain verification, webhooks, and delivery logs — built for the SRS ecosystem.

Everything you need to send email

REST API

Send emails with a simple JSON payload. Idempotency keys prevent duplicate sends.

SMTP Submission

Drop-in SMTP on port 587 with STARTTLS. Works with Node.js, Python, and any MTA client.

Domain Verification

SPF, DKIM, and DMARC setup with automated DNS checks.

Webhooks

Real-time delivery events with HMAC-SHA256 signed payloads.

Suppression Lists

Automatic hard bounce and complaint handling with manual overrides.

Delivery Logs

Full message lifecycle tracking from queued to delivered or bounced.

How it works

01

Verify your domain

Add SPF, DKIM, and DMARC records. Postline validates automatically.

02

Get API credentials

Create scoped API keys or SMTP credentials per project.

03

Send and track

Messages flow through NATS queues to MTA delivery with full event webhooks.

More email for less

Up to 10× the volume of Resend at a lower price. No daily sending limits on any plan.

Free

Free

3,000 emails / month

No daily sending limit

  • ✓ REST API + SMTP
  • ✓ 1 sending domain
  • ✓ All webhook events
  • ✓ No daily limit
  • ✓ 7-day delivery logs
  • ✓ Community support

Indie

$9/ month

25,000 emails / month

No daily sending limit

  • ✓ Everything in Free
  • ✓ 3 sending domains
  • ✓ 30-day delivery logs
  • ✓ Email support
  • ✓ No daily limit
  • ✓ Built for early-stage SaaS
Most popular

Pro

$19/ month

100,000 emails / month

No daily sending limit

  • ✓ Everything in Indie
  • ✓ 10 sending domains
  • ✓ Analytics dashboard
  • ✓ Priority queue
  • ✓ All webhook events
  • ✓ Email support

Scale

$79/ month

500,000 emails / month

No daily sending limit

  • ✓ Everything in Pro
  • ✓ Unlimited domains
  • ✓ Dedicated IP included
  • ✓ 99.9% uptime SLA
  • ✓ 90-day delivery logs
  • ✓ Priority support

Enterprise

3M+ emails/month, dedicated infrastructure, custom SLA, and priority onboarding.

Overage billed at $1 per 1,000 emails

Ready to send your first email?

Deploy on a single server with Docker Compose. Full stack in minutes.