> ## Documentation Index
> Fetch the complete documentation index at: https://docs.surnex.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Subscribe, or change plan

> With no paid subscription, answers a Stripe Checkout `url` to send the customer to. With one, changes its plan in place (prorated) and answers `changed: true` with no url. A move to a plan the organization already holds more than — 400 tracked keywords onto Starter — is refused with 409 and the `overages`.



## OpenAPI

````yaml https://api.surnex.io/docs/openapi.json post /v1/organizations/{orgId}/billing/checkout
openapi: 3.1.0
info:
  title: Surnex API
  version: 1.0.0
  description: >-
    The SEO platform's API.


    **The API is the product.** The dashboard is one client and the MCP server
    at `/mcp` is another. If a number needs deriving, a service derives it —
    never a React component, or the two clients drift.


    **Two kinds of auth.** The dashboard sends a Supabase access token as a
    Bearer JWT. MCP agents send `X-API-Key`, and the organization is resolved
    from the key.


    **Two data modes.** SERP results and Google Trends are fetched live on
    request. Everything else is written by the worker and read from Postgres, so
    a freshly-created project returns empty until its jobs complete.
servers:
  - url: https://api.surnex.io
    description: Surnex API
security: []
paths:
  /v1/organizations/{orgId}/billing/checkout:
    post:
      tags:
        - billing
      summary: Subscribe, or change plan
      description: >-
        With no paid subscription, answers a Stripe Checkout `url` to send the
        customer to. With one, changes its plan in place (prorated) and answers
        `changed: true` with no url. A move to a plan the organization already
        holds more than — 400 tracked keywords onto Starter — is refused with
        409 and the `overages`.
      parameters:
        - schema:
            type: string
            format: uuid
          required: true
          name: orgId
          in: path
      requestBody:
        content:
          application/json:
            schema:
              type: object
              properties:
                plan:
                  type: string
                  enum:
                    - starter
                    - growth
                    - agency
                    - scale
                interval:
                  type: string
                  enum:
                    - month
                    - year
                  default: month
                success_url:
                  type: string
                  format: uri
                cancel_url:
                  type: string
                  format: uri
              required:
                - plan
                - success_url
                - cancel_url
      responses:
        '200':
          description: Checkout URL, or the change made
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
                    enum:
                      - true
                  data:
                    type: object
                    nullable: true
                    properties:
                      url:
                        type: string
                        nullable: true
                      changed:
                        type: boolean
                    required:
                      - url
                      - changed
                required:
                  - success
                  - data
        '400':
          description: Already on that plan, or the plan cannot be bought yet
          content:
            application/json:
              schema:
                type: object
                properties: {}
        '409':
          description: >-
            The organization holds more than that plan allows;
            `details.overages` says what
          content:
            application/json:
              schema:
                type: object
                properties: {}

````

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