Postmark

Postmark Sender Signatures API

The Sender Signatures API API from Postmark — 5 operation(s) for sender signatures api.

GitHub OpenAPI

Operations 8

Each operation below carries the questions people ask an LLM about it and the instructions they give an agent to run it. Generated by API Evangelist overlay

GET /senders List sender signatures · Postmark List Sender Signatures #
Ask an LLM
“Which from addresses are registered as sender signatures on my account?”
“Can I page through all my sender signatures?”
Tell an agent
List the first {count} sender signatures.
Show my sender signatures after skipping {offset}.
POST /senders Register a new from address · Postmark Create a Sender Signature #
Ask an LLM
“How do I add a new from address so I can send email as it?”
“Can I set a reply-to address when creating a sender signature?”
Tell an agent
Create a sender signature for {from_email} named {name}.
Add sender {from_email} with replies going to {reply_to}.
GET /senders/{signatureid} Get a sender signature · Postmark Get a Sender Signature #
Ask an LLM
“Is my sender signature confirmed, and what DNS does it still need?”
“Can I view the settings of one sender signature?”
Tell an agent
Get sender signature {signatureid}.
Show the confirmation and DNS status of sender signature {signatureid}.
PUT /senders/{signatureid} Update a sender signature · Postmark Update a Sender Signature #
Ask an LLM
“How do I change the display name on an existing sender signature?”
“Can I change the reply-to address of a sender I already registered?”
Tell an agent
Rename sender signature {signatureid} to {name}.
Set the reply-to on sender signature {signatureid} to {reply_to}.
DELETE /senders/{signatureid} Delete a sender signature · Postmark Delete a Sender Signature #
Ask an LLM
“How do I remove a from address I no longer use?”
“Can I delete a sender signature from my account?”
Tell an agent destructive · confirm first
Delete sender signature {signatureid}.
Remove the from address registered as signature {signatureid}.
POST /senders/{signatureid}/resend Resend a sender confirmation email · Postmark Resend Signature Confirmation Email #
Ask an LLM
“The confirmation email for my new sender never arrived — can I get it resent?”
“How do I re-send the signature confirmation link?”
Tell an agent
Resend the confirmation email for sender signature {signatureid}.
Send the confirmation link for signature {signatureid} again.
POST /senders/{signatureid}/verifyspf Verify SPF for a sender signature · Postmark Request DNS Verification for SPF #
Ask an LLM
“How do I get SPF checked for a sender signature's domain?”
“Can I re-run the SPF verification on one of my sender signatures?”
Tell an agent
Verify SPF on sender signature {signatureid}.
Check the SPF DNS record behind sender signature {signatureid}.
POST /senders/{signatureid}/requestnewdkim Request a new DKIM key for a sender · Postmark Request a new DKIM Key #
Ask an LLM
“How do I get a fresh DKIM key for a sender signature?”
“Where do the pending DKIM host and value appear for a sender signature?”
Tell an agent
Request a new DKIM key for sender signature {signatureid}.
Generate fresh DKIM values for signature {signatureid} and show the pending records.

Documentation

📖
Documentation
https://postmarkapp.com/developer
📖
GettingStarted
https://postmarkapp.com/developer/api/overview
📖
Authentication
https://postmarkapp.com/developer/api/overview#authentication

Specifications

⚙
OpenAPI
https://raw.githubusercontent.com/api-evangelist/postmark/refs/heads/main/openapi/postmark-sender-signatures-api-api-openapi.yml
⚙
AsyncAPI
https://raw.githubusercontent.com/api-evangelist/postmark/refs/heads/main/asyncapi/postmark-webhooks-asyncapi.yml

Other Resources

🔗
Overlay
https://raw.githubusercontent.com/api-evangelist/postmark/refs/heads/main/overlays/postmark-sender-signatures-api-api-overlay.yaml

Work with this as data

Every API here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for apis

7 MCP tools reach this
  • find_apisBrowse and filter every API in the catalog.
  • get_api_artifactsOne API's artifacts, grouped by type.
  • get_openapiThe primary OpenAPI for this API.
  • find_similar_apisAPIs that look like this one.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools →

Call it yourself

curl for this page
This API 
curl "https://apis.io/api/v1/apis/postmark:postmark-sender-signatures-api-api"
All apis 
curl "https://apis.io/api/v1/apis?limit=25"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.

OpenAPI Specification

postmark-sender-signatures-api-api-openapi.yml Raw ↑ 
openapi: 3.2.0
info:
  title: Postmark Account Sender Signatures API
  description: 'Postmark makes sending and receiving email incredibly easy. The Account-level API allows users to

    configure all Servers, Domains, and Sender Signatures associated

    with an Account.'
  version: 0.9.0
servers:
- url: //api.postmarkapp.com/
tags:
- name: Sender Signatures API
paths:
  /senders:
    get:
      tags:
      - Sender Signatures API
      summary: Postmark List Sender Signatures
      operationId: listSenderSignatures
      parameters:
      - name: X-Postmark-Account-Token
        in: header
        description: The token associated with the Account on which this request will operate.
        required: true
        schema:
          type: string
      - name: count
        in: query
        description: Number of records to return per request. Max 500.
        required: true
        schema:
          maximum: 500
          minimum: 1
          type: integer
      - name: offset
        in: query
        description: Number of records to skip
        required: true
        schema:
          minimum: 0
          type: integer
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SenderListingResults'
        '422':
          description: An error was generated due to incorrect use of the API. See the Message associated with this response for more information.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StandardPostmarkResponse'
        '500':
          description: Indicates an internal server error occurred.
          content: {}
    post:
      tags:
      - Sender Signatures API
      summary: Postmark Create a Sender Signature
      operationId: createSenderSignature
      parameters:
      - name: X-Postmark-Account-Token
        in: header
        description: The token associated with the Account on which this request will operate.
        required: true
        schema:
          type: string
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/SenderSignatureCreationModel'
        required: false
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SenderSignatureExtendedInformation'
        '422':
          description: An error was generated due to incorrect use of the API. See the Message associated with this response for more information.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StandardPostmarkResponse'
        '500':
          description: Indicates an internal server error occurred.
          content: {}
      x-codegen-request-body-name: body
  /senders/{signatureid}:
    get:
      tags:
      - Sender Signatures API
      summary: Postmark Get a Sender Signature
      operationId: getSenderSignature
      parameters:
      - name: X-Postmark-Account-Token
        in: header
        description: The token associated with the Account on which this request will operate.
        required: true
        schema:
          type: string
      - name: signatureid
        in: path
        description: The ID for the Sender Signature that should be retrieved.
        required: true
        schema:
          type: integer
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SenderSignatureExtendedInformation'
        '422':
          description: An error was generated due to incorrect use of the API. See the Message associated with this response for more information.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StandardPostmarkResponse'
        '500':
          description: Indicates an internal server error occurred.
          content: {}
    put:
      tags:
      - Sender Signatures API
      summary: Postmark Update a Sender Signature
      operationId: editSenderSignature
      parameters:
      - name: X-Postmark-Account-Token
        in: header
        description: The token associated with the Account on which this request will operate.
        required: true
        schema:
          type: string
      - name: signatureid
        in: path
        description: The ID for the Sender Signature that should be modified by the request.
        required: true
        schema:
          type: integer
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/SenderSignatureEditingModel'
        required: false
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SenderSignatureExtendedInformation'
        '422':
          description: An error was generated due to incorrect use of the API. See the Message associated with this response for more information.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StandardPostmarkResponse'
        '500':
          description: Indicates an internal server error occurred.
          content: {}
      x-codegen-request-body-name: body
    delete:
      tags:
      - Sender Signatures API
      summary: Postmark Delete a Sender Signature
      operationId: deleteSenderSignature
      parameters:
      - name: X-Postmark-Account-Token
        in: header
        description: The token associated with the Account on which this request will operate.
        required: true
        schema:
          type: string
      - name: signatureid
        in: path
        description: The ID for the Sender Signature that should be deleted by the request.
        required: true
        schema:
          type: integer
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StandardPostmarkResponse'
        '422':
          description: An error was generated due to incorrect use of the API. See the Message associated with this response for more information.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StandardPostmarkResponse'
        '500':
          description: Indicates an internal server error occurred.
          content: {}
  /senders/{signatureid}/resend:
    post:
      tags:
      - Sender Signatures API
      summary: Postmark Resend Signature Confirmation Email
      operationId: resendSenderSignatureConfirmationEmail
      parameters:
      - name: X-Postmark-Account-Token
        in: header
        description: The token associated with the Account on which this request will operate.
        required: true
        schema:
          type: string
      - name: signatureid
        in: path
        description: The ID for the Sender Signature that should have its confirmation email resent.
        required: true
        schema:
          type: integer
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StandardPostmarkResponse'
        '422':
          description: An error was generated due to incorrect use of the API. See the Message associated with this response for more information.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StandardPostmarkResponse'
        '500':
          description: Indicates an internal server error occurred.
          content: {}
  /senders/{signatureid}/verifyspf:
    post:
      tags:
      - Sender Signatures API
      summary: Postmark Request DNS Verification for SPF
      operationId: requestSPFVerificationForSenderSignature
      parameters:
      - name: X-Postmark-Account-Token
        in: header
        description: The token associated with the Account on which this request will operate.
        required: true
        schema:
          type: string
      - name: signatureid
        in: path
        description: The ID for the Sender Signature for which SPF DNS records should be verified.
        required: true
        schema:
          type: integer
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SenderSignatureExtendedInformation'
        '422':
          description: An error was generated due to incorrect use of the API. See the Message associated with this response for more information.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StandardPostmarkResponse'
        '500':
          description: Indicates an internal server error occurred.
          content: {}
  /senders/{signatureid}/requestnewdkim:
    post:
      tags:
      - Sender Signatures API
      summary: Postmark Request a new DKIM Key
      description: 'Requests a new DKIM key to be created. Until the DNS entries are confirmed,

        the new values will be in the `DKIMPendingHost` and `DKIMPendingTextValue` fields.

        After the new DKIM value is verified in DNS, the pending values will migrate to

        `DKIMTextValue` and `DKIMPendingTextValue` and Postmark will begin to sign emails

        with the new DKIM key.'
      operationId: requestNewDKIMKeyForSenderSignature
      parameters:
      - name: X-Postmark-Account-Token
        in: header
        description: The token associated with the Account on which this request will operate.
        required: true
        schema:
          type: string
      - name: signatureid
        in: path
        description: The ID for the Sender Signature for which a new DKIM Key should be generated.
        required: true
        schema:
          type: integer
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StandardPostmarkResponse'
        '422':
          description: An error was generated due to incorrect use of the API. See the Message associated with this response for more information.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StandardPostmarkResponse'
        '500':
          description: Indicates an internal server error occurred.
          content: {}
components:
  schemas:
    StandardPostmarkResponse:
      type: object
      properties:
        ErrorCode:
          type: integer
        Message:
          type: string
      description: A Postmark API error.
    SenderSignatureExtendedInformation:
      type: object
      properties:
        Domain:
          type: string
        EmailAddress:
          type: string
          format: email
        ReplyToEmailAddress:
          type: string
          format: email
        Name:
          type: string
        Confirmed:
          type: boolean
        SPFVerified:
          type: boolean
        SPFHost:
          type: string
        SPFTextValue:
          type: string
        DKIMVerified:
          type: boolean
        WeakDKIM:
          type: boolean
        DKIMHost:
          type: string
        DKIMTestValue:
          type: string
        DKIMPendingHost:
          type: string
        DKIMPendingTextValue:
          type: string
        DKIMRevokedHost:
          type: string
        DKIMRevokedTextValue:
          type: string
        SafeToRemoveRevokedKeyFromDNS:
          type: boolean
        DKIMUpdateStatus:
          type: string
        ReturnPathDomain:
          type: string
        ReturnPathDomainVerified:
          type: boolean
        ReturnPathDomainCNAMEValue:
          type: string
        ID:
          type: integer
          format: int64
      description: ''
    SenderSignatureInformation:
      type: object
      properties:
        Domain:
          type: string
        EmailAddress:
          type: string
          format: email
        ReplyToEmailAddress:
          type: string
          format: email
        Name:
          type: string
        Confirmed:
          type: boolean
        ID:
          type: integer
          format: int64
      description: ''
    SenderListingResults:
      type: object
      properties:
        TotalCount:
          type: integer
        SenderSignatures:
          type: array
          items:
            $ref: '#/components/schemas/SenderSignatureInformation'
      description: ''
    SenderSignatureCreationModel:
      type: object
      properties:
        FromEmail:
          type: string
          format: email
        Name:
          type: string
        ReplyToEmail:
          type: string
          format: email
        ReturnPathDomain:
          type: string
      description: ''
    SenderSignatureEditingModel:
      type: object
      properties:
        Name:
          type: string
        ReplyToEmail:
          type: string
          format: email
        ReturnPathDomain:
          type: string
      description: ''