A single REST endpoint and TypeScript SDK handles transactional, marketing, and onboarding emails — with delivery guarantees, webhook events, and a 23ms average latency.
TypeScript SDK
Fully typed request and response objects, inline JSDoc, and autocompletion in every editor. Zero config required.
REST API
POST /v1/send from any language, edge runtime, or shell script. One endpoint, all email types.
SMTP relay
Drop-in credentials for legacy apps. Point your existing SMTP config at relay.sendbound.com and you are done.
Every request travels from your SDK through our API gateway into a durable delivery queue. We validate domains, apply rate limits, and assign an idempotency key before routing begins. Sendbound's own delivery network handles global routing, reputation management, and automatic failover — without any change to your code. Once delivered, our event pipeline signs and POSTs a webhook to your endpoint in real time.
Your Application
TypeScript SDK · REST API · SMTP relay
Sendbound API
Auth · rate-limit · idempotency · queue
Sendbound Delivery Network
Global routing
150+ edge nodes
Reputation engine
IP & domain scoring
Retry logic
Exp. backoff · 72h
Spam pre-flight
Score before send
Your webhook endpoint
delivered · opened · clicked · bounced
The same dependable send primitive, native to the language your team already uses.
Node.js
Python
Ruby
Go
PHP
.NETnpm install @sendbound/nodeFour steps. No boilerplate. No SMTP config. No XML.
$ npm install @sendbound/node
added 1 package in 0.8s
$ npm install @sendbound/react
added 1 package in 0.6s
✓ Ready to send
import { Sendbound } from '@sendbound/node'
export const sb = new Sendbound({
apiKey: process.env.SENDBOUND_KEY,
})
await sb.emails.send({
from: 'Acme <billing@acme.com>',
to: 'james@stripe.com',
subject: 'Invoice ready',
react: <InvoiceEmail />,
})
// ← { id: "em_8x9kzq3f", status: "queued" }
Invoice ready
em_8x9kzq3f
Welcome to Acme
em_7w2mxp1a
Payment confirmed
em_4k8rzn9c
avg delivery latency
API uptime SLA
emails sent to date
countries reached
Any team that sends programmatic email — from a two-person startup to a scaled platform — uses the same single endpoint.
Stop writing email infrastructure. One import, one API key, and every email type your product will ever need is covered — transactional, onboarding, notification, or marketing. TypeScript types catch mistakes at compile time instead of 2am.
The free tier gives you 3,000 emails a month, zero credit card required. Send a welcome email in under 5 minutes, then add webhooks, analytics, and suppression management as you grow.
Create isolated projects per customer, manage separate sending domains, and query audit logs per tenant. Idempotency keys make retries safe even when your own infrastructure is unreliable.
The features that every production email API needs — included by default, not gated behind an enterprise tier.
| Feature | Sendbound | Postmark | SendGrid | AWS SES |
|---|---|---|---|---|
| TypeScript SDK | ✓ | ✓ | ✓ | ✗ |
| Webhook delivery events | ✓ | ✓ | ✓ | Partial |
| React Email template rendering | ✓ | ✗ | ✗ | ✗ |
| Idempotency keys | ✓ | ✓ | ✗ | ✗ |
| SMTP relay (drop-in for legacy apps) | ✓ | ✓ | ✓ | ✓ |
| SDK for 6+ languages | ✓ | ✓ | ✓ | ✗ |
| Batch send endpoint | ✓ | ✓ | ✓ | ✓ |
| 30-day email log retention | ✓ | ✓ | ✗ | ✗ |
| Global suppression list | ✓ | ✓ | ✓ | ✗ |
| GDPR-compliant data residency option | ✓ | ✗ | Partial | ✗ |
| Free tier (emails/month) | ✓ | ✗ | ✗ | ✓ |
| 23ms average delivery latency | ✓ | ✗ | ✗ | ✗ |
The REST API offers typed payloads, idempotency, React rendering, and delivery events. SMTP relay is a compatibility layer for existing applications that cannot change their sending integration yet.
Yes. Pass a React Email component through the Node SDK and Sendbound renders it before delivery. You can also send HTML, text, or templates created in the dashboard.
Add an Idempotency-Key to a request and Sendbound stores its result for 24 hours. Retrying the same operation returns the original email rather than creating a duplicate send.
The API is available globally with edge routing, and delivery is orchestrated from US and European infrastructure. Select a preferred data region for your workspace when compliance requires it.
Limits scale with account reputation and plan. Responses include standard rate-limit headers, and queued sends are smoothed automatically so a burst never silently loses mail.
Keep your current templates and switch the endpoint or SMTP hostname first. Our migration guide maps SendGrid fields to Sendbound and an import tool brings over approved contacts and suppression lists.