Postmark

Connect AI agents to Postmark. Agents send single, templated, and batch transactional email, search outbound messages and bounces, manage message-stream suppressions, and read delivery statistics.

16 actions available

A new customer record is created upstream

Agent reads the fields the template needs from the record

Agent sends the welcome with Send Email with Template

Agent runs Get Message Details to confirm the delivery timeline

Agent reads Get Delivery Stats to watch for a spike in inactives

Deliverability channel gets an alert if inactives climb

A reactivation of a bounced address routes for approval first

What This Integration Enables

An agent can send a single email with HTML and plain-text bodies, open and link tracking, tags, and attachments, send from a template driven by a variable model, or dispatch up to 500 messages in a single batch call. It lists and reads templates, lists the message streams on the server, and searches sent and queued messages with filtering, so a flow can find exactly the message it needs and read its full delivery timeline. Around the send, the agent monitors and maintains deliverability. It returns aggregate outbound and delivery statistics, searches and reads bounces, reactivates a bounced address, and manages a message stream's suppression list. Postmark exposes no event triggers in this integration, so flows start from the systems feeding it: a database, a store, or a scheduled sweep. The agent is the bridge that turns those signals into tracked, deliverable mail and keeps the delivery record honest.

Without FlowRunner

Delivery is a black box No one knows whether a transactional email actually landed

Bounces pile up silently Hard-bounced addresses sit deactivated with no follow-up

Templates edited blind A template change ships without a check on what it renders

With FlowRunner

Delivery is queryable Get Message Details returns the full open and click timeline per message

Bounces triaged The agent searches bounces and surfaces them for follow-up

Streams and templates read first The agent inspects the template and stream before sending

Use Case Scenarios

Personalized Welcome From a Record

An [Airtable](/integrations/airtable) On New Record trigger fires for a new customer. The agent calls Send Email with Template to deliver a personalized welcome rendered from the record's fields, then reads Get Message Details to confirm the message was delivered before closing the flow.

Receipt With the Invoice Attached

On a new order in [Stripe](/integrations/stripe), the agent calls Stripe Get Invoice, then Send Email to email the customer their receipt with the invoice PDF attached. The receipt goes out the moment the order closes, not on the next manual batch.

Deliverability Watch

A scheduled flow calls Get Delivery Stats and watches the count of inactive addresses. When it spikes, the agent posts an alert to a team channel with [Slack](/integrations/slack) Send Message To Channel, and separately searches bounces and logs each to [Google Sheets](/integrations/google-sheets) Add Rows for follow-up.

Human-in-Loop Highlight

Reactivating a bounced address tells Postmark to attempt delivery to an address that already failed, which can quietly damage sender reputation if the bounce was a real hard failure. When the agent is about to run Activate Bounce, it treats the reactivation as a [human-in-the-loop](/concepts/human-in-the-loop/) step. It pauses, shows the address, the bounce type, and the SMTP detail behind the original failure, and routes the decision to a deliverability owner through Slack or email. The owner approves, and the agent reactivates. The owner holds, and the address stays suppressed. The agent handles the routine triage; the call that touches reputation gets a human.

Agent processes routinely

Detects exception requiring judgment

Clear match Continues automatically

Ambiguous Routes to human via Slack

Human decides

Agent resumes with decision

Agent Capabilities

16 actions

Sending

Send Email Sends a single email through Postmark. Supports HTML and plain-text bodies, up to 50 CC and BCC recipients, open and link tracking, tags, and attachments taken from FlowRunner file URLs.
Send Email with Template Sends an email using a Postmark template, identified by template ID, with a variable model that supplies the substitution values.
Send Batch Emails Sends up to 500 emails in a single API call, each with its own recipients and content.

Templates and Streams

List Templates Lists the templates on your Postmark server, with pagination and optional filtering.
Get Template Retrieves a single template's full details, including its subject line and HTML and text bodies.
List Message Streams Lists the message streams on your server (transactional, inbound, and broadcast), so the agent sends on the right stream.

Messages

Search Outbound Messages Searches sent and queued messages with pagination and filtering by recipient and other criteria.
Get Message Details Retrieves full details of a sent message by its message ID, including the bodies and the delivery, open, and click event timeline.

Statistics and Bounces

Get Outbound Overview Returns aggregate sending statistics for your server: sent, bounced, and spam-complaint counts.
Get Delivery Stats Returns the number of inactive (suppressed) addresses on your server and a breakdown by reason.
Search Bounces Searches bounces with pagination and filtering by bounce type and active or inactive state.
Get Bounce Retrieves full details of a single bounce by its ID, including the bounce type and SMTP detail.
Activate Bounce Reactivates a bounced address so Postmark will attempt delivery to it again.

Suppressions

List Suppressions Lists the suppressed addresses on a message stream, addresses Postmark will not send to.
Create Suppression Adds one or more addresses to a message stream's suppression list, preventing Postmark from sending to them.
Delete Suppression Removes one or more addresses from a message stream's suppression list so Postmark can send to them again.

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