Postmark API

Name: Postmark API API
Brand: Postmark Server API
Availability: InStock

✓ Official Vendor SpecCommunicationsEmail DeliveryapiKey43 EndpointsREST

For Agents

Send transactional emails, manage bounces, track delivery statistics, render templates, and process inbound messages for a specific Postmark server.

Quickstart

Get started with Postmark API in minutes using your preferred integration method.

# Add to your MCP client config (Claude Desktop, Cursor, Windsurf)
{
  "jentic": {
    "url": "https://api.jentic.com/mcp",
    "auth": "oauth"
  }
}

# Then ask your agent:
"send a transactional email"

# → Jentic returns the GET /events tool with parameter schema, agent executes.

Capabilities

What an agent can do with Postmark API API.

Send single and batch transactional emails with HTML, plain text, and template rendering

Track bounced emails with detailed dump data and trigger reactivation for resolved addresses

Monitor delivery statistics including opens, clicks, spam complaints, and bounce rates

Manage email templates with validation and server-level template storage

GET STARTED

Start building with Postmark API API

Explore with Jentic

View OpenAPI Document

Use Cases

Patterns agents use Postmark API API for, with concrete tasks.

★ Transactional Email Delivery

Send transactional emails such as password resets, order confirmations, and shipping notifications. The Postmark API supports single message sending via /email, batch sending via /email/batch, and template-based sending via /email/withTemplate. Each request returns a message ID for tracking delivery status, opens, and clicks through the statistics endpoints.

Send a transactional email via POST /email/withTemplate with a template alias, recipient address, and template model variables, then verify delivery via GET /messages/outbound/{messageid}/details

Bounce Management and Recovery

Monitor and manage email bounces to maintain sender reputation. The API provides bounce listing with filtering, detailed bounce dump information for diagnosis, and address reactivation for resolved delivery issues. Agents can identify patterns in bounce reasons, alert on spike events, and automatically reactivate addresses after infrastructure fixes.

Retrieve all bounces from GET /bounces filtered to the last 24 hours, identify hard bounces, and reactivate any addresses where the bounce reason was a temporary infrastructure issue using PUT /bounces/{bounceid}/activate

Email Engagement Analytics

Track email open rates, click-through rates, and engagement patterns by platform, email client, and geographic location. The API provides aggregate statistics via /stats/outbound endpoints and per-message detail via /messages/outbound/opens and /messages/outbound/clicks. Agents can compile engagement dashboards and identify underperforming message types.

Retrieve outbound email statistics from GET /stats/outbound for the last 30 days, then pull open rates by email client from GET /stats/outbound/opens/emailclients and compile a summary of engagement by client

AI Agent Email Operations

Enable AI agents to send transactional emails and monitor delivery through Jentic. Agents can discover email sending operations by intent, send templated messages, check bounce status, and pull analytics without hardcoding API paths or managing server tokens directly.

Search Jentic for 'send a transactional email with a template', load the operation schema for POST /email/withTemplate, and execute with recipient, template alias, and template variables

Key Endpoints

43 endpoints — the postmark server api provides transactional email sending, bounce management, delivery statistics, template handling, and inbound message processing across 43 endpoints.

METHOD

PATH

DESCRIPTION

POST

/email

Send a single email message

POST

/email/withTemplate

Send an email using a template

POST

/email/batch

Send a batch of emails

GET

/bounces

List bounced messages

PUT

/bounces/{bounceid}/activate

Reactivate a bounced address

GET

/stats/outbound

Get outbound delivery statistics

GET

/messages/outbound

Search outbound message history

GET

/templates

List email templates on the server

POST

/email

Send a single email message

POST

/email/withTemplate

Send an email using a template

POST

/email/batch

Send a batch of emails

GET

/bounces

List bounced messages

PUT

/bounces/{bounceid}/activate

Reactivate a bounced address

Why though Jentic?

Three things that make agents converge on Jentic-routed access.

Credential isolation

Postmark server tokens (X-Postmark-Server-Token header) are stored encrypted in the Jentic vault. Agents receive scoped access that injects the token automatically — raw server credentials never enter the agent context.

Intent-based discovery

Agents search by intent (e.g., 'send a transactional email') and Jentic returns matching Postmark Server operations with parameter schemas, so agents can send emails and check bounces without memorizing endpoint paths.

Time to first call

Direct Postmark integration: 1-2 days for token management, template setup, and bounce handling logic. Through Jentic: under 30 minutes — search, load schema, execute.

Related APIs

Alternatives and complements available in the Jentic catalogue.

Complementary

Postmark Account-level API

Account infrastructure management — servers, domains, and sender signatures

Choose the Account API when you need to manage servers, verify domains, or configure sender signatures — the Server API handles email sending and delivery tracking.

Alternative

SendGrid Mail API

High-volume email delivery with advanced templating and scheduling

Choose SendGrid when you need high-volume sending with dedicated IPs, advanced scheduling, and marketing email support — Postmark specializes in fast transactional delivery with simpler configuration.

Alternative

Mandrill API

Transactional email from Mailchimp with merge tags and conditional content

Choose Mandrill when you need deep Mailchimp integration and merge-tag templating — Postmark offers faster delivery speeds and simpler bounce management for pure transactional use cases.

FAQs

Specific to using Postmark API API through Jentic.

What authentication does the Postmark Server API use?

The Postmark Server API uses a server token passed in the X-Postmark-Server-Token header with every request. Each server in your account has its own token. Through Jentic, server tokens are stored encrypted in the credential vault and injected automatically — agents never handle raw tokens directly.

Can I send batch emails with the Postmark Server API?

Yes. POST to /email/batch sends up to 500 messages in a single request. Each message in the batch can have different recipients, subjects, and content. For template-based batch sending, use POST /email/batchWithTemplates to render different template variables per recipient.

What are the rate limits for the Postmark Server API?

Postmark does not impose traditional rate limits. Instead, sending is governed by your account's sending credits and reputation. Batch endpoints accept up to 500 messages per request. If you exceed your plan's monthly volume, additional messages are queued rather than rejected.

How do I send a templated email through Jentic?

Search Jentic for 'send email with template', load the operation schema for POST /email/withTemplate, and execute with the template alias, recipient email, and a model object containing your template variables. Jentic handles the X-Postmark-Server-Token injection. Install with pip install jentic and sign up at https://app.jentic.com/sign-up.

Can I track email opens and clicks with this API?

Yes. GET /stats/outbound/opens returns aggregate open statistics, and GET /messages/outbound/opens/{messageid} shows opens for a specific message. Similarly, /stats/outbound/clicks provides click analytics. Both support breakdowns by email client, platform, and browser family.

How do I handle bounced emails with the Postmark API?

GET /bounces lists all bounced messages with filtering by type, date, and status. GET /bounces/{bounceid}/dump provides the raw SMTP response for diagnosis. Once an issue is resolved, PUT /bounces/{bounceid}/activate reactivates the address so future sends are attempted rather than suppressed.