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Event-Driven Transactional MessagingEvent Triggered Messaging

Transform inbound webhooks into delivered transactional emails in milliseconds

Turn events from Stripe, GitHub, Shopify, Clerk, or custom services into immediate customer alerts. Built for high-concurrency event loops with automated retries and dead-letter queues.

3,000 emails/month freeZero credit card requiredSub-20ms edge latency
202 Accepted
Event Processing
Queued durably before any provider call
6,000
Free Monthly Sends
Forever free tier
100%
DLQ Retry Support
Zero dropped events
Developer Ergonomics

Drop into your application in under 60 seconds

Native typed interfaces with zero unnecessary dependencies. Built for standard fetch and modern edge runtimes.

$npm install sadasend
webhook-handler.ts
typescript
TYPESCRIPT
import { SadaSend } from 'sadasend';

const sadasend = new SadaSend(process.env.SADASEND_API_KEY!);

export async function handleWebhookEvent(req: Request) {
  const event = await req.json();

  if (event.type === 'payment.succeeded') {
    await sadasend.emails.send({
      from: 'billing@yourdomain.com',
      to: event.data.customer_email,
      subject: `Payment Confirmation: $${(event.data.amount / 100).toFixed(2)}`,
      html: `<p>Your payment of <strong>$${(event.data.amount / 100).toFixed(2)}</strong> was received.</p>`,
      tags: ['webhook-event', event.type]
    });
  }

  return new Response(JSON.stringify({ received: true }), { status: 200 });
}
Core Infrastructure

Engineered for high deliverability and zero incident risk

Every layer from edge connection pooling to per-key rate limits is designed to keep critical transactional dispatches fast, reliable, and contained.

High Concurrency Event Loops

Handles sudden traffic spikes and bulk webhook bursts without queuing bottlenecks or timeout failures.

Built-in Dead-Letter Queue (DLQ)

Monitor failed deliveries in the dashboard with 1-click retry mechanisms, ensuring zero lost messages from transient network glitches.

Cryptographic Signature Verification

Verify inbound and outbound webhook signatures with HMAC-SHA256 headers to prevent unauthorized event tampering.

low-latency Edge Ingestion

Respond to incoming webhook webhooks immediately, preventing third-party event dispatchers from triggering timeout retries.

Architectural Comparison

SadaSend vs Traditional SMTP in Webhooks

Invoking blocking SMTP connections inside webhook handlers causes timeouts and dropped event retries. SadaSend REST dispatches in under 20ms.

Feature & CapabilitySadaSendTraditional SMTP in Webhooks
Webhook Timeout RiskZero — a single HTTP responseHigh (SMTP handshakes > 1s)
Automatic Idempotency Key Guard
Dead-Letter Queue (DLQ) Inspector
Event Tagging & Filtering
Forever Free Tier
Transparent Economics

Start with 3,000 emails every month at zero cost

No artificial paywalls on security. Unlike legacy providers that reserve recipient allowlists or dedicated IP pools for high enterprise tiers, every SadaSend account receives full safety controls from day one.

3,000 dispatches monthly forever with zero credit card
All safety gates, allowlists, and velocity limits included
Scale seamlessly: Starter ($12/mo for 10k), Pro ($19/mo for 50k), Scale ($79/mo for 250k)
Free Developer Plan
$0 / mo

No credit card required

Create Free AccountCompare all paid plan tiers
Frequently Asked Questions

Everything you need to know about webhook email API

Clear, transparent answers on deliverability, API authentication, and rate limits.

Pass the incoming webhook event ID as an Idempotency-Key header or idempotencyKey option in the SDK. SadaSend deduplicates requests received within 24 hours automatically.
Technical Deep Dives

Related developer guides and architectural tutorials

Explore step-by-step production implementation blueprints, benchmarks, and protocols.

Documentation

REST API Reference & Endpoints

Complete REST API reference for sending emails, managing API keys, tracking delivery events, and configuring recipient allowlists with low latency.

Read guide
Documentation

Official Client SDKs (TypeScript & Python)

Official zero-dependency client SDKs for SadaSend. TypeScript and Python packages are live on npm and PyPI with typed results and auto-idempotency.

Read guide
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