Postmarkapp Postmark API
Browse all Postmarkapp APIs✓ 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.
Use for: I need to send a transactional email using a template, I want to check the bounce rate for my sending server, List all bounced email addresses in the last 7 days, Get delivery statistics for outbound emails including open rates
Not supported: Does not handle account-level infrastructure (server provisioning, domain management, sender signatures) — use for sending emails, tracking delivery, and managing bounces on a single server only.
The Postmark Server API provides transactional email sending, bounce management, delivery statistics, template handling, and inbound message processing across 43 endpoints. It supports single and batch email delivery with template rendering, bounce tracking with reactivation workflows, open and click analytics by platform and browser, inbound email processing with rule-based triggers, and server-level configuration.
Install Jentic One Beta
Connect the Postmark API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Postmark API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.
Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.
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Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh
jentic register # connects your agent to your Jentic One instanceJentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.
Capabilities
What an agent can do with Postmark 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
Process inbound emails with configurable trigger rules for routing and automation
Analyze engagement metrics by email client, platform, browser family, and geographic location
Retrieve detailed message history for both outbound and inbound email traffic
Use Cases
Patterns agents use Postmark 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
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
GET
/stats/outbound
Get outbound delivery statistics
GET
/messages/outbound
Search outbound message history
GET
/templates
List email templates on the server
Why 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.
FAQs
Specific to using Postmark 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.
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