# Postmark API

**Provider:** ActiveCampaign
**Category:** communication
**Base URL:** `https://api.postmarkapp.com`
**Auth:** api-key — `X-Postmark-Server-Token: YOUR_SERVER_TOKEN`
**Rate Limit:** 50 requests/sec
**Free Tier:** Yes — [object Object]
**Pricing:** Free tier available (freemium)
**Docs:** https://postmarkapp.com/developer

## Description

Postmark specializes in reliable transactional email delivery — think password resets, receipts, and notifications. It maintains dedicated sending infrastructure (separate from marketing email) to maximize inbox delivery rates. Features include DKIM/SPF/DMARC support, bounce and spam complaint tracking, click/open tracking, HTML + text templates, and message streams for organizing different email types.

## Endpoints

| Method | Endpoint | Description |
|--------|----------|-------------|
| POST | `https://api.postmarkapp.com/email` | Send a single transactional email |
| POST | `https://api.postmarkapp.com/email/batch` | Send up to 500 emails in one API call |
| POST | `https://api.postmarkapp.com/email/withTemplate` | Send email using a stored template with variables |
| GET | `https://api.postmarkapp.com/messages/outbound` | List sent messages with delivery status |
| GET | `https://api.postmarkapp.com/bounces` | List bounced emails with bounce type and detail |
| GET | `https://api.postmarkapp.com/stats/outbound` | Delivery stats: open rates, click rates, bounces |

## Authentication

Pass your Server API token in the X-Postmark-Server-Token request header. Find it in Postmark → Server → API Tokens.

```
X-Postmark-Server-Token: YOUR_SERVER_TOKEN
```

## Sample Request

```bash
curl "https://api.postmarkapp.com/email" \
  -H "X-Postmark-Server-Token: $POSTMARK_SERVER_TOKEN" \
  -H "Content-Type: application/json" \
  -X POST \
  -d '{"From":"sender@example.com","To":"user@example.com","Subject":"Your order is confirmed","HtmlBody":"<h1>Order #1234 confirmed!</h1>","MessageStream":"outbound"}'
```

## Sample Response

```json
{
  "To": "user@example.com",
  "SubmittedAt": "2024-03-15T10:00:00.0000000-05:00",
  "MessageID": "b7bc2f4a-e38e-4336-af2d-1b5e6c9b4ed5",
  "ErrorCode": 0,
  "Message": "OK"
}
```

## Pricing Details

Free: 100 emails/mo. PAYG: $1.50/1k emails. Monthly: from $15/mo (10k emails). Volume discounts start at 300k emails.

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*Source: [API Map](https://apimap.dev/apis/postmark/) — CC BY 4.0*