Customer.io Subscription Center API

openapi: 3.2.0
info:
  version: 1.0.0
  title: Customer.io App Subscription Center 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: Subscription Center
  description: 'A subscription center differentiates the types of messages available for your product. Your audience sets subscription preferences by name, but we record subscription preferences by topic ID. You can use these endpoints to get a list of topics and names, helping you understand your audience''s subscription preferences.

    '
paths:
  /v1/subscription_topics:
    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 subscription topics
      operationId: getTopics
      security:
      - Bearer-Auth: []
      description: "Returns a list of subscription topics in your workspace. If there are no topics, it returns an empty array.       \n"
      tags:
      - Subscription Center
      responses:
        '200':
          description: Returns an array of `topics`.
          content:
            application/json:
              schema:
                type: object
                properties:
                  topics:
                    type: array
                    items:
                      type: object
                      properties:
                        name:
                          type: string
                          description: The name of the subscription topic.
                          example: Product Updates
                        description:
                          type: string
                          description: A description of the topic that you provided when you created the topic in the UI.
                          example: For people who want updates on product releases.
                        subscribed_by_default:
                          type: boolean
                          description: If false, a person is opted-out by default. If true, a person is opted-in by default.
                          example: false
                        id:
                          type: integer
                          description: The system-generated id for the subscription topic. Also located on the subscription center landing page. These increment up by 1, starting with 1.
                          example: 4
                        identifier:
                          type: string
                          description: The key associated with the subscription topic. The format is `topic_<id>`.
                          example: topic_4
        '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/subscription_topics"
      - 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/subscription_topics\",\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/subscription_topics")


          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/subscription_topics")


          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/subscription_topics\"\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/subscription_center/{customer_id}/token:
    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: Generate a subscription center token
      operationId: getSubscriptionCenterToken
      security:
      - Bearer-Auth: []
      description: 'Generates a signed token and URL for a person''s standalone subscription center page. The token is valid for 24 hours.


        Use the returned `url` to link people to a hosted subscription center page where they can manage their subscription preferences outside of a message. This is useful when you want to provide a direct link to the subscription center—for example, in your app''s account settings or in a custom email.


        The `customer_id` path parameter is the person''s identifier (e.g. an email address or customer ID) as it appears in Customer.io. The identifier must match an existing person in your workspace.

        '
      tags:
      - Subscription Center
      parameters:
      - name: customer_id
        in: path
        required: true
        description: The identifier for a person in your workspace—the same value you'd use as an `id` or `email` to identify a person in Customer.io.
        schema:
          type: string
          example: person@example.com
      responses:
        '200':
          description: Returns a signed `token` and a subscription center `url` for the person.
          content:
            application/json:
              schema:
                type: object
                properties:
                  token:
                    type: string
                    description: 'A signed token representing the person''s subscription center session. The token expires after 24 hours.


                      If you want to use a custom link tracking domain, you can point your customers to `https://<your-tracking-domain>/u/i/<your-token>/<language-code (optional)>`.

                      '
                  url:
                    type: string
                    description: A full URL to the person's standalone subscription center page. You can use this URL directly as a link.
                    example: https://track.customer.io/u/i/<your-token>/
        '400':
          description: The `customer_id` is invalid or does not match a known person in your workspace.
          content:
            application/json:
              schema:
                type: object
                properties:
                  errors:
                    type: array
                    items:
                      type: object
                      properties:
                        detail:
                          type: string
                          example: bad request
                        status:
                          type: string
                          example: '400'
      x-codeSamples:
      - lang: Shell + Curl
        source: "curl --request GET \\\n  --header 'Authorization: Bearer REPLACE_BEARER_TOKEN' \\\n  --url https://api.customer.io/v1/subscription_center/{customer_id}/token"
      - 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/subscription_center/%7Bcustomer_id%7D/token\",\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/subscription_center/%7Bcustomer_id%7D/token")


          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/subscription_center/%7Bcustomer_id%7D/token")


          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/subscription_center/%7Bcustomer_id%7D/token\"\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/subscription_channels:
    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 subscription channels
      operationId: getChannels
      security:
      - Bearer-Auth: []
      description: 'Returns a list of subscription channels available in your workspace. Channels represent the delivery methods that people can subscribe to or unsubscribe from—email, SMS, push, etc. If you haven''t set up channel options in your subscription center, this endpoint returns an empty array.

        '
      tags:
      - Subscription Center
      responses:
        '200':
          description: Returns an array of `channels`.
          content:
            application/json:
              schema:
                type: object
                properties:
                  channels:
                    type: array
                    items:
                      type: object
                      properties:
                        id:
                          type: integer
                          description: The system-generated ID for the subscription channel.
                          example: 1
                        type:
                          type: string
                          description: The type of delivery channel.
                          enum:
                          - email
                          - twilio
                          - urban_airship
                          - slack
                          - push
                          - in_app
                          - line
                          - inbox
                          - whatsapp
                          example: email
                        name:
                          type: string
                          description: The display name of the subscription channel.
                          example: Email
                        description:
                          type: string
                          description: A description of the channel.
                          example: Email messages
                        subscribed_by_default:
                          type: boolean
                          description: If false, a person is opted-out by default. If true, a person is opted-in by default.
                          example: 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/subscription_channels"
      - 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/subscription_channels\",\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/subscription_channels")


          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/subscription_channels")


          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/subscription_channels\"\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}"
components:
  securitySchemes:
    Bearer-Auth:
      type: http
      scheme: bearer
      description: 'The App API uses a bearer authentication scheme.


        You can generate a bearer token, known as an **App API Key**, with a defined scope in [your account settings](https://fly.customer.io/settings/api_credentials?keyType=app). [Learn more about bearer authorization in Customer.io](/accounts/settings/managing-credentials).

        '
    ServiceAccount-Auth:
      x-scalar-ignore: true
      type: http
      scheme: bearer
      bearerFormat: sa_live_
      description: 'Transactional send endpoints (`/v1/send/email`, `/v1/send/push`, `/v1/send/sms`, `/v1/send/in_app`, `/v1/send/inbox_message`) also accept a service-account bearer token, prefixed with `sa_live_`. Service-account tokens work across workspaces, so you must pass the target workspace as the `X-Workspace-Id` header on each request.


        Service-account tokens are intended for testing and one-off sends—for example, using the Customer.io CLI with an AI agent like Claude to verify that a transactional message renders correctly before wiring it into your production backend. **For the production integration that triggers the message from your application, use an App API Key instead**: it''s workspace-scoped, easier to rotate, and has a smaller blast radius.


        Service-account tokens are server-side credentials. Treat them like any API key—keep them in environment variables or a secret manager, and never embed them in client-side code, mobile apps, or other untrusted contexts.

        '
    bearerAuth:
      type: http
      scheme: bearer
      description: API key passed as a Bearer token