Build with ApiMailer

Quickstart

Send your first email in under five minutes.

1. Create an account

Sign up for a free ApiMailer account. No credit card required.

2. Add and verify your domain

Add your sending domain in the dashboard and configure the DNS records we provide (SPF and DKIM). Verification is usually instant once the records propagate.

3. Generate an API key

Navigate to Settings → API Keys and create a new key. Copy it somewhere safe — it won't be shown again.

4. Send your first email

curl -X POST https://api.apimailer.com/v1/send \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "hello@yourdomain.com",
    "to": "user@example.com",
    "subject": "Hello from ApiMailer!",
    "html": "<h1>It works!</h1><p>Your first email via ApiMailer.</p>"
  }'

Authentication

All API requests require a valid API key sent in the Authorization header using Bearer token format:

Authorization: Bearer YOUR_API_KEY

API keys can be created and managed from the dashboard. Each key can be scoped with specific permissions:

Base URL

All API requests should be made to:

https://api.apimailer.com/v1

All requests must use HTTPS. HTTP requests will be rejected.

Errors

ApiMailer uses standard HTTP status codes. Errors return a JSON body with a code and message field:

{
  "error": {
    "code": "validation_error",
    "message": "The 'to' field is required.",
    "field": "to"
  }
}

Send Email

Send a single email message.

Parameters

Response

{
  "id": "msg_8f3k2j5n9x",
  "status": "queued",
  "from": "hello@yourdomain.com",
  "to": ["user@example.com"],
  "created_at": "2026-02-13T10:30:00Z"
}

Batch Send

Send up to 1,000 individual emails in a single API call. Each message can have unique recipients, subjects, and content.

{
  "messages": [
    {
      "from": "hello@yourdomain.com",
      "to": "user1@example.com",
      "subject": "Welcome!",
      "template_id": "tmpl_welcome",
      "variables": { "name": "Alice" }
    },
    {
      "from": "hello@yourdomain.com",
      "to": "user2@example.com",
      "subject": "Welcome!",
      "template_id": "tmpl_welcome",
      "variables": { "name": "Bob" }
    }
  ]
}

Templates

Create reusable email templates with dynamic variables.

Templates use {{variable}} syntax for dynamic content, with support for conditionals and loops:

<h1>Welcome, {{name}}!</h1>
<p>Thanks for joining {{company}}.</p>

{{#if has_coupon}}
  <p>Use code <strong>{{coupon_code}}</strong> for 20% off.</p>
{{/if}}

Add Domain

Register a new sending domain with ApiMailer.

{
  "domain": "yourdomain.com"
}

{
  "id": "dom_abc123",
  "domain": "yourdomain.com",
  "status": "pending",
  "dns_records": [
    { "type": "TXT", "name": "@", "value": "v=spf1 include:_spf.apimailer.com ~all" },
    { "type": "TXT", "name": "am._domainkey", "value": "v=DKIM1; k=rsa; p=MIGf..." }
  ]
}

Verify Domain

Trigger a verification check for your domain's DNS records.

Webhooks

Receive real-time notifications when email events occur. Configure webhook endpoints in the dashboard or via the API.

{
  "event": "delivered",
  "timestamp": "2026-02-13T10:30:05Z",
  "message_id": "msg_8f3k2j5n9x",
  "recipient": "user@example.com",
  "tags": ["welcome"],
  "metadata": {
    "smtp_response": "250 OK"
  }
}

All webhook payloads include an X-ApiMailer-Signature header that you should verify to ensure authenticity.

Event Types

SMTP Relay

Use ApiMailer as an SMTP relay for existing applications. Configure your application with these settings:

Rate Limits

API requests are rate limited based on your plan:

When you exceed the rate limit, the API returns a 429 status with a Retry-After header indicating how many seconds to wait.