Postmark is a transactional email delivery service focused on speed and deliverability for application email. The Nexla connector uses the Postmark REST API to send transactional and template-based email, and to read delivery statistics, bounces, message activity, and open events. Authenticate with a Postmark Server API Token to move data between Postmark and the rest of your stack.
Power end-to-end data operations for your Postmark API with Nexla. Our bi-directional Postmark connector is purpose-built for Postmark, making it simple to ingest data, sync it across systems, and deliver it anywhere — all with no coding required. Nexla turns API-sourced data into ready-to-use, reusable data products and makes it easy to send data to Postmark or any other destination. With comprehensive monitoring, lineage tracking, and access controls, Nexla keeps your Postmark workflows fast, secure, and fully governed.
Features
Type: API
SourceDestination
Seamless API Integration: Connect to any endpoint as source or destination without coding, with automatic data product creation
Visual Composition & Chaining: Build complex integrations using visual templates, chain API calls, and compose workflows with data validation and filtering
API Proxy: Expose curated slices of your data securely with a secure and customizable API proxy that validates and transforms data on the fly
Request optimization with intelligent batching, retry, and caching to minimize API calls and costs
Before configuring Postmark in Nexla, you need a Postmark account with an active server and a Server API Token. Postmark authenticates API requests with the X-Postmark-Server-Token HTTP header, and the token scopes access to a single Postmark server (its messages, bounces, statistics, and templates).
To obtain your Server API Token, follow these steps:
Select the server you want to connect to from your list of servers, or create a new server if you don't have one yet.
Open the API Tokens tab for that server.
Copy the Server API Token shown on the tab. This token is available to Account Owners, Account Admins, and users with Server Admin privileges.
Store the token securely, as it grants access to send email and read message data for that Postmark server. If the token is ever compromised, regenerate it from the same API Tokens tab.
The base URL for all requests is https://api.postmarkapp.com. For detailed information about API tokens, request formats, and available endpoints, see the Postmark Developer Documentation.
After selecting the data source/destination type, click the Add Credential tile to open the Add New Credential overlay.
Enter a name for the credential in the Credential Name field and a short, meaningful description in the Credential Description field.
Complete the remaining fields in the overlay as prompted, then save the credential.
Postmark scopes each Server API Token to a single server. If you work with multiple Postmark servers, create a separate credential for each so that flows read from and write to the correct server.
For detailed information about authentication, request formats, and available endpoints, see the Postmark Developer Documentation.
Click the Save button at the bottom of the overlay. The newly added credential will now appear in a tile on the Authenticate screen during data source/destination creation.
To create a new data flow, navigate to the Integrate section, and click the New Data Flow button. Select the Postmark connector tile, then select the credential that will be used to connect to Postmark, and click Next; or, create a new Postmark credential for use in this flow.
Nexla provides pre-built templates that can be used to rapidly configure data sources to ingest data from common Postmark endpoints. Select the endpoint from which this source will fetch data from the Endpoint pulldown menu. Available endpoint templates are listed in the expandable boxes below.
[Rest API] Get delivery stats
This endpoint template retrieves delivery statistics for your Postmark server, including counts of sent messages and the breakdown of bounce types. Use it to monitor overall deliverability and track email performance over time.
This template calls the delivery stats endpoint and returns a single summary object for the server associated with your credential. For details about the response fields, see the Postmark Developer Documentation.
[Rest API] Get bounces
This endpoint template retrieves a list of bounces recorded for your Postmark server. Use it to analyze failed deliveries, monitor bounce reasons, and identify inactive recipients.
The template exposes optional query parameters — including count, offset, type, inactive, email filter, message ID, tag, and a from/to date range — that let you page through and narrow the set of bounces returned.
Leave the optional parameters blank to retrieve bounces with Postmark's default behavior, or set them to filter the results. For the full list of accepted values, see the Postmark Developer Documentation.
[Rest API] Get a single bounce
This endpoint template retrieves the details of a single bounce identified by its bounce ID. Use it to inspect an individual failed delivery, including its type, description, and affected recipient.
Supply the Bounceid parameter to identify which bounce to fetch.
The bounce ID is returned by the Get bounces endpoint. For details about the bounce object, see the Postmark Developer Documentation.
[Rest API] Get bounce dump
This endpoint template retrieves the raw source (dump) of a bounced message identified by its bounce ID. Use it when you need the full content of the bounced email for troubleshooting.
Supply the Bounceid parameter to identify which bounce dump to fetch.
This endpoint template searches the outbound messages sent from your Postmark server. Use it to audit sent email, track message status, and pull message activity for reporting.
The template exposes optional query parameters — including count, offset, recipient, from email, tag, status, and a from/to date range — to page through and filter the messages returned.
Leave the optional parameters blank to retrieve outbound messages with Postmark's default behavior, or set them to narrow the results. For the full list of accepted values, see the Postmark Developer Documentation.
[Rest API] Outbound message details
This endpoint template retrieves the full details of a single outbound message identified by its message ID, including recipients, metadata, and the message event history.
Supply the Messageid parameter to identify which outbound message to fetch.
The message ID is returned by the Outbound message search endpoint. For details about the response, see the Postmark Developer Documentation.
[Rest API] Outbound message dump
This endpoint template retrieves the raw source (dump) of a single outbound message identified by its message ID. Use it when you need the complete content of a sent email.
Supply the Messageid parameter to identify which outbound message dump to fetch.
This endpoint template searches the inbound messages received by your Postmark server. Use it to audit incoming email, track processing status, and pull inbound activity for reporting.
The template exposes optional query parameters — including count, offset, recipient, from email, subject, mailbox hash, tag, status, and a from/to date range — to page through and filter the messages returned.
Leave the optional parameters blank to retrieve inbound messages with Postmark's default behavior, or set them to narrow the results. For the full list of accepted values, see the Postmark Developer Documentation.
[Rest API] Inbound message details
This endpoint template retrieves the full details of a single inbound message identified by its message ID, including sender, recipients, and the message event history.
Supply the Messageid parameter to identify which inbound message to fetch.
The message ID is returned by the Inbound message search endpoint. For details about the response, see the Postmark Developer Documentation.
[Rest API] Opens for all messages
This endpoint template retrieves open events for outbound messages sent from your Postmark server. Use it to analyze recipient engagement, including the email client, operating system, and geographic location associated with each open.
The template exposes optional query parameters — including count, offset, recipient, tag, client and OS attributes, platform, and country/region/city — to page through and filter the open events returned.
Open tracking must be enabled on your Postmark server for open events to be recorded. For the full list of accepted values, see the Postmark Developer Documentation.
Once the selected endpoint template has been configured, click the Test button to the right of the endpoint selection menu to retrieve a sample of the data that will be fetched. Sample data will be displayed in the Endpoint Test Result panel on the right, allowing you to verify that the source is configured correctly before saving.
Postmark data sources can also be manually configured to ingest data from any valid Postmark API endpoint, including endpoints not covered by the pre-built templates, chained API calls, or custom request parameters. Select the Advanced tab at the top of the configuration screen, and follow the instructions in Connect to Any API to configure the API method, endpoint URL, date/time and lookup macros, path to data, metadata, and request headers.
Once all of the relevant settings have been configured, click the Create button in the upper right corner of the screen to save and create the new Postmark data source. Nexla will now begin ingesting data from the configured endpoint and will organize any data that it finds into one or more Nexsets.
Click the + icon on the Nexset that will be sent to the Postmark destination, and select the Send to Destination option from the menu. Select the Postmark connector from the list of available destination connectors, then select the credential that will be used to connect to Postmark, and click Next; or, create a new Postmark credential for use in this flow.
Nexla provides pre-built templates that can be used to rapidly configure destinations to send data to common Postmark endpoints. Select the endpoint to which data will be sent from the Endpoint pulldown menu. Then, click on the template in the list below to expand it, and follow the instructions to configure additional endpoint settings.
[Rest API] Send a single email
This endpoint template sends a single transactional email through Postmark using records from a Nexset. Each record is sent as one API request containing the message fields (sender, recipients, subject, and body).
Each Nexset record must contain the fields required by the Postmark email API. For the full request format, see the Postmark Developer Documentation.
[Rest API] Send a batch of emails
This endpoint template sends a batch of transactional emails through Postmark in a single request. Use it to deliver multiple messages efficiently from a Nexset.
The request body must contain an array of message objects in the format required by the Postmark batch email API. For details, see the Postmark Developer Documentation.
[Rest API] Activate a bounce
This endpoint template reactivates a bounced address so that Postmark will attempt delivery to it again. Use it to clear an inactive recipient after the underlying delivery issue has been resolved.
Supply the Bounceid parameter to identify which bounce to activate.
[Rest API] Bypass rules for a blocked inbound message
This endpoint template bypasses the inbound processing rules for a blocked inbound message, allowing Postmark to process a message that was previously blocked by a rule.
Supply the Messageid parameter to identify which inbound message to bypass.
The message ID is returned by the Inbound message search source endpoint. For details, see the Postmark Developer Documentation.
[Rest API] Retry a failed inbound message for processing
This endpoint template retries processing for an inbound message whose delivery to your inbound webhook previously failed.
Supply the Messageid parameter to identify which inbound message to retry.
The message ID is returned by the Inbound message search source endpoint. For details, see the Postmark Developer Documentation.
[Rest API] Send an email using a Template
This endpoint template sends a single transactional email rendered from a Postmark template. Provide the template ID or alias and the template model values in each Nexset record.
The referenced template must already exist on your Postmark server. For the request format and template model, see the Postmark Developer Documentation.
[Rest API] Send a batch of email using templates
This endpoint template sends a batch of template-based transactional emails in a single request. Use it to deliver multiple templated messages efficiently from a Nexset.
The request body must contain an array of message objects, each referencing a template ID or alias and its model. For details, see the Postmark Developer Documentation.
[Rest API] Create a Template
This endpoint template creates a new email template on your Postmark server using records from a Nexset. Use it to provision templates programmatically from your Nexla flows.
Each record must contain the template fields (such as name, subject, and body) required by the Postmark template API. For details, see the Postmark Developer Documentation.
[Rest API] Update a Template
This endpoint template updates an existing email template on your Postmark server.
Supply the Templateidoralias parameter to identify which template to update.
The referenced template must already exist on your Postmark server. For the request format, see the Postmark Developer Documentation.
[Rest API] Delete a Template
This endpoint template deletes an email template from your Postmark server.
Supply the Templateidoralias parameter to identify which template to delete.
Postmark destinations can also be manually configured to send data to any valid Postmark API endpoint. Select the Advanced tab at the top of the configuration screen, and follow the instructions in Connect to Any API to configure the API method, data format, endpoint URL, request headers, attribute exclusions, record batching, and response webhooks.
Postmark APIs expect JSON request bodies. For endpoints that act on a specific resource, include the bounce ID, message ID, or template ID/alias required by the endpoint.
Once all endpoint settings have been configured, click the Done button in the upper right corner of the screen to save and create the destination. To send the data to the configured Postmark endpoint, open the destination resource menu, and select Activate.
The Nexset data will not be sent to the Postmark endpoint until the destination is activated. Destinations can be activated immediately or at a later time, providing full control over data movement.
