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OverviewStart here

First-party docs · human and LLM ready

Email infrastructure docs without the guesswork.

Start with a verified domain and one send, then expand into audiences, broadcasts, templates, webhooks, receiving, MCP, and self-hosted operations. This docs shell renders the same markdown corpus that powers /docs/llms.txt.

Send your first email Self-hosting guide OpenAPI

217

markdown guides

OpenAPI

schema source

MCP

agent tooling

Quickstart

Base URL: https://opensend.namuh.co

Node.js

import { Resend } from "opensend";

const resend = new Resend(process.env.OPENSEND_API_KEY);

const { data, error } = await resend.emails.send({
  from: "OpenSend <onboarding@updates.example.com>",
  to: ["user@example.com"],
  subject: "Hello from OpenSend",
  html: "<strong>It works.</strong>",
});

if (error) throw error;
console.log(data);

cURL

curl -X POST https://opensend.namuh.co/emails \
  -H "Authorization: Bearer os_YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: welcome-user-123" \
  -d '{
    "from": "OpenSend <onboarding@updates.example.com>",
    "to": ["user@example.com"],
    "subject": "Hello from OpenSend",
    "html": "<strong>It works.</strong>"
  }'

Recommended path

Do these four things first

1 · API key

Authenticate requests

Create an os_ API key and use Bearer auth. Dashboard cookies are not API credentials.

2 · Domain

Verify a sending domain

Add DNS records for DKIM, SPF, DMARC, bounce handling, and optional tracking.

3 · Send

Send your first email

Use the OpenSend API or SDK to send, schedule, batch, tag, and inspect messages.

4 · Observe

Watch logs and webhooks

Track lifecycle events, signed webhook deliveries, retries, and API request logs.

Docs library

Browse by job to be done

API reference

Endpoint contracts, auth, pagination, errors, limits, and OpenAPI.

SDKs

TypeScript, Python, Go, Ruby, and framework-specific send examples.

Migrate from Resend

Verifier CLI usage, compatibility statuses, sandbox dry-run planning, and migration caveats.

Domains

DNS setup, Cloudflare automation, DMARC, tracking, and provider guidance.

Audience

Contacts, segments, topics, properties, preferences, and suppressions.

Broadcasts and templates

Campaign creation, template variables, versioning, and performance tracking.

Self-hosting

Docker Compose, migrations, SES/SNS ingester, security, and observability.

Popular endpoints

Common API surface

Use the styled reference for humans and OpenAPI for exact schemas.

POST/emails

Send one email

POST/emails/batch

Queue a batch

POST/emails/:email_id/cancel

Cancel scheduled email

POST/contacts

Create contact

POST/broadcasts/:id/send

Send broadcast

POST/api/webhooks

Create webhook