Customer.io Transactional API

openapi: 3.2.0
info:
  version: 1.0.0
  title: Customer.io App Transactional API
  description: 'Our App API provides ways to trigger messages and retrieve information about people, campaigns, broadcasts, and more.


    # Overview


    The App API provides methods to send newsletters, transactional messages, and API-triggered broadcasts. You can create newsletters from scratch and update transactional messages and API-triggered broadcasts.


    For transactional messages and API-triggered broadcasts, your payload acts as a message "trigger" and can contain `data` that you reference in your messages using liquid—`{{trigger.<data>}}`.


    The other endpoints help you retrieve information about people, segments, campaigns, broadcasts, etc; it also lets you update campaign actions, messages, newsletter variants, etc. Aside from the [API-triggered broadcast](#triggerBroadcast) (1 per 10 seconds) and [Transactional](#sendEmail) (100 per second) endpoints, requests are limited to 10 per second.


    # Use our Postman collection


    We''ve generated a Postman collection to help you get started with our APIs.


    If you fork this collection, you might want to disable the *Watch original collection* option. We automatically update our Postman collection whenever we release changes to our documentation, even if we don''t change our APIs—which happens daily! Rather than being flooded with Postman notifications, you can check out our [Release Notes](/release-notes/) for updates to our APIs.


    **NOTE**: Postman endpoints default to our US APIs. If you''re in our European (EU) region, you''ll need to add `-eu` to the server variables (`track_api_url` and `app_api_url`).


    [<img src="https://run.pstmn.io/button.svg" alt="Run In Postman" style="width: 128px; height: 32px;">](https://god.gw.postman.com/run-collection/23697545-2931c004-e63d-4cdc-bf4b-e685ba6da42d?action=collection%2Ffork&source=rip_markdown&collection-url=entityId%3D23697545-2931c004-e63d-4cdc-bf4b-e685ba6da42d%26entityType%3Dcollection%26workspaceId%3Db886877f-fc09-475f-84fe-6221a98f4d18#?env%5BCustomer.io%20API%20Environment%5D=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)


    # Server addresses: US and EU


    Customer.io hosts services in the United States (US) and European Union. Select the appropriate server address for your region.


    | Region | Server Address |

    | :-- | :-- |

    | US | https://api.customer.io |

    | EU | https://api-eu.customer.io |


    # Authentication


    All requests to the Customer.io App API use an [App API Key](#App-API-Key).


    To authenticate, provide your key as a Bearer token in a HTTP Authorization header. You can create and manage your API keys—including keys with different scopes—in [your account settings page](https://fly.customer.io/settings/api_credentials?keyType=app). Each operation on this page references the authorization header it requires.


    # Rate Limits


    Most endpoints on this page are limited to 10 requests per second. The exceptions are:

    * The [transactional email](#operation/sendEmail) endpoint is limited to 100 requests per second.

    * The [API-triggered broadcast endpoint](#operation/triggerBroadcast) is limited to 1 request every 10 seconds.


    **Rate limits are subject to change. We may adjust these thresholds to ensure stable performance for all customers.**

    '
servers:
- url: https://api.customer.io
  description: The base URL for broadcasts, transactional messages, and data-retrieval APIs. These endpoints use bearer authorization, and require a [token that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
- url: https://api-eu.customer.io
  description: The base URL for broadcasts, transactional messages, and data-retrieval APIs (EU region). These endpoints use bearer authorization, and require a [token that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
tags:
- name: Transactional
  x-displayName: Transactional Messages
  description: 'Send, and return information about, transactional messages. Transactional messages are messages that your audience explicitly requests or expects, like purchase receipts or password reset requests.


    The `transactional_id` in requests represents the transactional message template. Each individual send—the instance of a message sent to an individual person—is called a "delivery".

    '
paths:
  /v1/transactional:
    servers:
    - url: https://api.customer.io
      description: This API uses bearer authorization, requiring a [token that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    get:
      summary: List transactional messages
      operationId: listTransactional
      security:
      - Bearer-Auth: []
      description: Returns a list of your transactional messages—the transactional IDs that you use to trigger an individual transactional delivery. This endpoint does not return information about deliveries (instances of a message sent to a person) themselves.
      tags:
      - Transactional
      responses:
        '200':
          description: Returns an array of transactional messages.
          content:
            application/json:
              schema:
                type: object
                properties:
                  messages:
                    type: array
                    items:
                      x-scalar-ignore: true
                      description: Contains information about a transactional message.
                      type: object
                      properties:
                        id:
                          type: integer
                          description: The identifier Customer.io assigned to the transactional message
                          example: 2
                        name:
                          type: string
                          description: The name you set for the transactional message.
                          example: password reset
                        description:
                          type: string
                          description: A description of the transactional message.
                          example: sends a temporary password and lets the customer reset their password.
                        send_to_unsubscribed:
                          type: boolean
                          description: If true, people with an `unsubscribed` attribute set to `true` can trigger the message.
                        link_tracking:
                          type: boolean
                          description: If true, link tracking is enabled for this message.
                        open_tracking:
                          type: boolean
                          description: If true, open-tracking is enabled for this message.
                        hide_message_body:
                          type: boolean
                          description: If true, message contents are not retained in delivery history—you cannot recall the exact contents of the message.
                        queue_drafts:
                          type: boolean
                          description: If true, messages do not send automatically, and queue as drafts instead. You must send drafts through the *Deliveries & Drafts* page in the user interface.
                        created_at:
                          x-scalar-ignore: true
                          type: integer
                          format: unix timestamp
                          description: The date time when the referenced ID was created.
                          example: 1552341937
                          readOnly: true
                        updated_at:
                          x-scalar-ignore: true
                          type: integer
                          format: unix timestamp
                          description: The date time when the referenced ID was last updated.
                          example: 1552341937
                          readOnly: true
        '429':
          description: Your request is over the 10-per-second limit.
      x-codeSamples:
      - lang: Shell + Curl
        source: "curl --request GET \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/transactional"
      - lang: Node + Native
        source: "const http = require(\"https\");\n\nconst options = {\n  \"method\": \"GET\",\n  \"hostname\": \"api.customer.io\",\n  \"port\": null,\n  \"path\": \"/v1/transactional\",\n  \"headers\": {}\n};\n\nconst req = http.request(options, function (res) {\n  const chunks = [];\n\n  res.on(\"data\", function (chunk) {\n    chunks.push(chunk);\n  });\n\n  res.on(\"end\", function () {\n    const body = Buffer.concat(chunks);\n    console.log(body.toString());\n  });\n});\n\nreq.end();"
      - lang: Ruby + Native
        source: 'require ''uri''

          require ''net/http''

          require ''openssl''


          url = URI("https://api.customer.io/v1/transactional")


          http = Net::HTTP.new(url.host, url.port)

          http.use_ssl = true

          http.verify_mode = OpenSSL::SSL::VERIFY_NONE


          request = Net::HTTP::Get.new(url)


          response = http.request(request)

          puts response.read_body'
      - lang: Python + Python3
        source: 'import http.client


          conn = http.client.HTTPSConnection("api.customer.io")


          conn.request("GET", "/v1/transactional")


          res = conn.getresponse()

          data = res.read()


          print(data.decode("utf-8"))'
      - lang: Go + Native
        source: "package main\n\nimport (\n\t\"fmt\"\n\t\"net/http\"\n\t\"io/ioutil\"\n)\n\nfunc main() {\n\n\turl := \"https://api.customer.io/v1/transactional\"\n\n\treq, _ := http.NewRequest(\"GET\", url, nil)\n\n\tres, _ := http.DefaultClient.Do(req)\n\n\tdefer res.Body.Close()\n\tbody, _ := ioutil.ReadAll(res.Body)\n\n\tfmt.Println(res)\n\tfmt.Println(string(body))\n\n}"
  /v1/transactional/{transactional_id}:
    servers:
    - url: https://api.customer.io
      description: This API uses bearer authorization, requiring a [token that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    parameters:
    - name: transactional_id
      description: The identifier of your transactional message. You'll find this in the UI or URL of your transactional message. For example, if this is the path of a transactional message URL - `/transactional/3/templates/139` - the `transactional_id` is 3.
      in: path
      required: true
      schema:
        type: integer
    get:
      operationId: getTransactional
      summary: Get a transactional message
      security:
      - Bearer-Auth: []
      description: Returns information about an individual transactional message.
      tags:
      - Transactional
      responses:
        '200':
          description: Returns metadata for the transactional message ID in the path.
          content:
            application/json:
              schema:
                type: object
                properties:
                  message:
                    x-scalar-ignore: true
                    description: Contains information about a transactional message.
                    type: object
                    properties:
                      id:
                        type: integer
                        description: The identifier Customer.io assigned to the transactional message
                        example: 2
                      name:
                        type: string
                        description: The name you set for the transactional message.
                        example: password reset
                      description:
                        type: string
                        description: A description of the transactional message.
                        example: sends a temporary password and lets the customer reset their password.
                      send_to_unsubscribed:
                        type: boolean
                        description: If true, people with an `unsubscribed` attribute set to `true` can trigger the message.
                      link_tracking:
                        type: boolean
                        description: If true, link tracking is enabled for this message.
                      open_tracking:
                        type: boolean
                        description: If true, open-tracking is enabled for this message.
                      hide_message_body:
                        type: boolean
                        description: If true, message contents are not retained in delivery history—you cannot recall the exact contents of the message.
                      queue_drafts:
                        type: boolean
                        description: If true, messages do not send automatically, and queue as drafts instead. You must send drafts through the *Deliveries & Drafts* page in the user interface.
                      created_at:
                        x-scalar-ignore: true
                        type: integer
                        format: unix timestamp
                        description: The date time when the referenced ID was created.
                        example: 1552341937
                        readOnly: true
                      updated_at:
                        x-scalar-ignore: true
                        type: integer
                        format: unix timestamp
                        description: The date time when the referenced ID was last updated.
                        example: 1552341937
                        readOnly: true
        '404':
          description: The transactional message does not exist.
        '429':
          description: Your request is over the 10-per-second limit.
      x-codeSamples:
      - lang: Shell + Curl
        source: "curl --request GET \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/transactional/{transactional_id}"
      - lang: Node + Native
        source: "const http = require(\"https\");\n\nconst options = {\n  \"method\": \"GET\",\n  \"hostname\": \"api.customer.io\",\n  \"port\": null,\n  \"path\": \"/v1/transactional/%7Btransactional_id%7D\",\n  \"headers\": {}\n};\n\nconst req = http.request(options, function (res) {\n  const chunks = [];\n\n  res.on(\"data\", function (chunk) {\n    chunks.push(chunk);\n  });\n\n  res.on(\"end\", function () {\n    const body = Buffer.concat(chunks);\n    console.log(body.toString());\n  });\n});\n\nreq.end();"
      - lang: Ruby + Native
        source: 'require ''uri''

          require ''net/http''

          require ''openssl''


          url = URI("https://api.customer.io/v1/transactional/%7Btransactional_id%7D")


          http = Net::HTTP.new(url.host, url.port)

          http.use_ssl = true

          http.verify_mode = OpenSSL::SSL::VERIFY_NONE


          request = Net::HTTP::Get.new(url)


          response = http.request(request)

          puts response.read_body'
      - lang: Python + Python3
        source: 'import http.client


          conn = http.client.HTTPSConnection("api.customer.io")


          conn.request("GET", "/v1/transactional/%7Btransactional_id%7D")


          res = conn.getresponse()

          data = res.read()


          print(data.decode("utf-8"))'
      - lang: Go + Native
        source: "package main\n\nimport (\n\t\"fmt\"\n\t\"net/http\"\n\t\"io/ioutil\"\n)\n\nfunc main() {\n\n\turl := \"https://api.customer.io/v1/transactional/%7Btransactional_id%7D\"\n\n\treq, _ := http.NewRequest(\"GET\", url, nil)\n\n\tres, _ := http.DefaultClient.Do(req)\n\n\tdefer res.Body.Close()\n\tbody, _ := ioutil.ReadAll(res.Body)\n\n\tfmt.Println(res)\n\tfmt.Println(string(body))\n\n}"
  /v1/transactional/{transactional_id}/contents:
    servers:
    - url: https://api.customer.io
      description: This API uses bearer authorization, requiring a [token that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    parameters:
    - name: transactional_id
      description: The identifier of your transactional message. You'll find this in the UI or URL of your transactional message. For example, if this is the path of a transactional message URL - `/transactional/3/templates/139` - the `transactional_id` is 3.
      in: path
      required: true
      schema:
        type: integer
    get:
      operationId: listTransactionalVariants
      summary: List all variants of a transactional message
      security:
      - Bearer-Auth: []
      description: Returns the content variants of a transactional message, where each variant represents a different language.
      tags:
      - Transactional
      responses:
        '200':
          description: Returns each variant of the transactional message.
          content:
            application/json:
              schema:
                type: object
                properties:
                  contents:
                    type: array
                    description: Each object represents one of the variants.
                    items:
                      x-scalar-ignore: true
                      allOf:
                      - x-scalar-ignore: true
                        type: object
                        properties:
                          id:
                            x-scalar-ignore: true
                            description: The identifier for an action.
                            type: integer
                            readOnly: true
                            example: 96
                          name:
                            type: string
                            description: The name of the transactional message.
                            readOnly: true
                            example: Receipt
                          created:
                            x-scalar-ignore: true
                            type: integer
                            format: unix timestamp
                            description: The date time when the referenced ID was created.
                            example: 1552341937
                            readOnly: true
                          updated:
                            x-scalar-ignore: true
                            type: integer
                            format: unix timestamp
                            description: The date time when the referenced ID was last updated.
                            example: 1552341937
                            readOnly: true
                          body:
                            type: string
                            description: The body of the transactional message. You cannot modify the body if you created it with our drag-and-drop editor.
                          language:
                            x-scalar-ignore: true
                            type: string
                            description: The language variant for your message. If you don't use our [localization feature](/journeys/channels/localization/getting-started), or this is the default message, this value is an empty string.
                            example: fr
                            readOnly: true
                          type:
                            type: string
                            description: The type of message.
                            enum:
                            - email
                            - push
                            readOnly: true
                          from:
                            x-scalar-ignore: true
                            type: string
                            description: The address that the message is from, relevant if the action `type` is `email`.
                            readOnly: true
                            example: sentFrom@example.com
                          from_id:
                            x-scalar-ignore: true
                            type: integer
                            description: The identifier of the `from` address, commonly known as the "sender". Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
                            example: 1
                          reply_to:
                            x-scalar-ignore: true
                            type: string
                            description: The address that receives replies for the message, if applicable.
                            readOnly: true
                            example: replyto@example.com
                          reply_to_id:
                            x-scalar-ignore: true
                            type:
                            - integer
                            - 'null'
                            description: The identifier for the `reply_to` address, if applicable. Use [List sender identities](#tag/sender-identities/listSenders) to find valid IDs.
                            example: 38
                          preprocessor:
                            x-scalar-ignore: true
                            type: string
                            description: If CSS pre-processing is enabled, this key is populated with `premailer`. Note, Juice replaced Premailer as the pre-processor, but you will only see `premailer` as the value.
                            enum:
                            - premailer
                            readOnly: true
                          recipient:
                            x-scalar-ignore: true
                            description: The recipient address for an action.
                            type: string
                            example: '{{customer.email}}'
                          subject:
                            x-scalar-ignore: true
                            type: string
                            description: The subject line for an `email` action.
                            example: Did you get that thing I sent you?
                          cc:
                            x-scalar-ignore: true
                            readOnly: true
                            description: The carbon-copy address(es) for this action.
                            type: string
                          bcc:
                            x-scalar-ignore: true
                            readOnly: true
                            description: The blind-copy address(es) for this action.
                            type: string
                          fake_bcc:
                            x-scalar-ignore: true
                            readOnly: true
                            type: boolean
                            description: 'If true, rather than sending true copies to BCC addresses, Customer.io sends a copy of the message with the subject line containing the recipient address(es).

                              '
                          preheader_text:
                            x-scalar-ignore: true
                            type: string
                            description: '[Also known as "preview text"](/journeys/channels/email/headers/custom-preheader-text/), this is the small block of text shown in an email inbox next to or underneath the subject line.

                              '
                          body_amp:
                            x-scalar-ignore: true
                            type: string
                            description: AMP-enabled content for your email. If a recipient's email client doesn't support AMP, they receive your `body` content instead. Make sure you're [set up to send AMP](/journeys/channels/email/layouts/amp-for-email/) first.
                      - type: object
                        properties:
                          headers:
                            x-scalar-ignore: true
                            description: A JSON string containing header objects with `name` and `value`. Names and values must be strings, with no non-ASCII characters or spaces. You can't overwrite reserved headers.
                            type: string
                            format: json
                            example: '[{"name":"X-Mailgun-Tag","value":"my-cool-tag"},{"name":"X-Custom-Header","value":"custom-value"}]'
        '400':
          description: The request was malformed.
          content:
            application/json:
              schema:
                type: object
                properties:
                  meta:
                    type: object
                    description: Contains errors.
                    properties:
                      error:
                        type: string
                        description: Describes the error that caused your request to fail.
        '404':
          description: The `transactional_id` or `content_id` in your request do not exist.
      x-codeSamples:
      - lang: Shell + Curl
        source: "curl --request GET \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/transactional/{transactional_id}/contents"
      - lang: Node + Native
        source: "const http = require(\"https\");\n\nconst options = {\n  \"method\": \"GET\",\n  \"hostname\": \"api.customer.io\",\n  \"port\": null,\n  \"path\": \"/v1/transactional/%7Btransactional_id%7D/contents\",\n  \"headers\": {}\n};\n\nconst req = http.request(options, function (res) {\n  const chunks = [];\n\n  res.on(\"data\", function (chunk) {\n    chunks.push(chunk);\n  });\n\n  res.on(\"end\", function () {\n    const body = Buffer.concat(chunks);\n    console.log(body.toString());\n  });\n});\n\nreq.end();"
      - lang: Ruby + Native
        source: 'require ''uri''

          require ''net/http''

          require ''openssl''


          url = URI("https://api.customer.io/v1/transactional/%7Btransactional_id%7D/contents")


          http = Net::HTTP.new(url.host, url.port)

          http.use_ssl = true

          http.verify_mode = OpenSSL::SSL::VERIFY_NONE


          request = Net::HTTP::Get.new(url)


          response = http.request(request)

          puts response.read_body'
      - lang: Python + Python3
        source: 'import http.client


          conn = http.client.HTTPSConnection("api.customer.io")


          conn.request("GET", "/v1/transactional/%7Btransactional_id%7D/contents")


          res = conn.getresponse()

          data = res.read()


          print(data.decode("utf-8"))'
      - lang: Go + Native
        source: "package main\n\nimport (\n\t\"fmt\"\n\t\"net/http\"\n\t\"io/ioutil\"\n)\n\nfunc main() {\n\n\turl := \"https://api.customer.io/v1/transactional/%7Btransactional_id%7D/contents\"\n\n\treq, _ := http.NewRequest(\"GET\", url, nil)\n\n\tres, _ := http.DefaultClient.Do(req)\n\n\tdefer res.Body.Close()\n\tbody, _ := ioutil.ReadAll(res.Body)\n\n\tfmt.Println(res)\n\tfmt.Println(string(body))\n\n}"
  /v1/transactional/{transactional_id}/content/{content_id}:
    servers:
    - url: https://api.customer.io
      description: This API uses bearer authorization, requiring a [token that you generate in the UI](https://fly.customer.io/settings/api_credentials?keyType=app).
    parameters:
    - name: transactional_id
      description: The identifier of your transactional message. You'll find this in the UI or URL of your transactional message. For example, if this is the path of a transactional message URL - `/transactional/3/templates/139` - the `transactional_id` is 3.
      in: path
      required: true
      schema:
        type: integer
    - name: content_id
      description: The content variant of your transactional message. You'll find the id in the URL of your transactional message. For example, if this is the path of a transactional message URL - `/transactional/3/templates/139` - the `content_id` is 139.
      in: path
      required: true
      schema:
        type: integer
    put:
      operationId: updateTransactional
      summary: Update a transactional message
      security:
      - Bearer-Auth: []
      description: "Update the body of a transactional email. This fully overwrites your existing transactional message. We'll use your updated content for any future transactional requests (`/v1/send/email`), so make sure that you test your message before you update it. \n\n**NOTE**: You cannot manage content made with Design Studio with this endpoint. Use the [Design Studio APIs](#tag/design-studio) instead.\n"
      tags:
      - Transactional
      requestBody:
        content:
          application/json:
            schema:
              x-scalar-ignore: true
              allOf:
              - x-scalar-ignore: true
                type: object
                properties:
                  id:
                    x-scalar-ignore: true
                    description: The identifier for an action.
                    type: integer
                    readOnly: true
                    example: 96
                  name:
                    type: string
                    description: The name of the transactional message.
                    readOnly: true
                    example: Receipt
                  created:
                    x-scalar-ignore: true
                    type: integer
                    format: unix timestamp
                    description: The date time when the referenced ID was created.
                    example: 1552341937
                    readOnly: true
                  updated:
                    x-scalar-ignore: true
                    type: integer
                    format: unix timestamp
                    description: The date time when the referenced ID was last updated.
                    example: 1552341937
                    readOnly: true
                  body:
                    type: string
                    description: The body of the transactional message. You cannot modify the body if you created it with our drag-and-drop editor.
                  language:
                    x-scalar-ignore: true
                    type: string
                    description: The language variant for your message. If you don't use our [localization feature](/journeys/channels/localization/getting-started), or this is the default message, this value is an empty

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# Full source: https://raw.githubusercontent.com/api-evangelist/customer-io/refs/heads/main/openapi/customer-io-transactional-api-openapi.yml