> ## Documentation Index > Fetch the complete documentation index at: https://docs.hyperprop.com/llms.txt > Use this file to discover all available pages before exploring further. # Buy Market Depth > Returns the URL of a secure checkout page. The trader pays the full current calendar month at the flat monthly price (`priceCents` in the status; no partial-month pricing, no tax added). Signing up during the last days of a month — on or after the renewal charge day — also pays next month. The card is saved for automatic renewal. After paying the trader returns to `returnPath` with `?depth_checkout=success` (or `=cancelled`); the add-on turns on within about a minute. 409 when the add-on is already on (use the renewal endpoint to turn auto-renew back on). ## OpenAPI ````yaml /api-reference/openapi.json post /v1/user/addons/market-depth/checkout openapi: 3.0.0 info: title: Hyperprop Platform API version: 1.0.0 description: >- REST API for the Hyperprop Trading Platform — provision evaluation and funded trading accounts, manage traders and plans, react to account lifecycle events via signed webhooks, and reconcile billing. Built for prop firms integrating from their own backend. Authentication, quick start, error handling, idempotency, pagination, custom metadata, webhooks, and the MCP connector are documented at https://docs.hyperprop.com. x-logo: url: https://app.hyperprop.com/logo-icon.svg altText: Hyperprop href: https://hyperprop.com servers: - url: https://api.hyperprop.com/platform description: Production security: [] tags: - name: Authentication description: >- User authentication - signup, signin, signout, password reset, email verification, OAuth, and MFA - name: User description: >- User account management - profile, notifications, agreements, dismissals, and audit logs. Requires Bearer token. - name: Organization description: >- Organization management - profile, team, trading accounts, plans, and rules. Supports **dual authentication**: Bearer JWT token (dashboard users) OR X-API-Key (programmatic access). - name: Market Data description: CME futures contracts and market data. Requires Bearer token. - name: Indicator Builder description: >- AI-assisted authoring of custom Hyperprop Script indicators for the web terminal. Requires Bearer token. - name: System description: System endpoints - health checks and connectivity paths: /v1/user/addons/market-depth/checkout: post: tags: - User summary: Buy Market Depth description: >- Returns the URL of a secure checkout page. The trader pays the full current calendar month at the flat monthly price (`priceCents` in the status; no partial-month pricing, no tax added). Signing up during the last days of a month — on or after the renewal charge day — also pays next month. The card is saved for automatic renewal. After paying the trader returns to `returnPath` with `?depth_checkout=success` (or `=cancelled`); the add-on turns on within about a minute. 409 when the add-on is already on (use the renewal endpoint to turn auto-renew back on). operationId: postV1UserAddonsMarketdepthCheckout requestBody: content: application/json: schema: $ref: '#/components/schemas/Model759' responses: '200': description: Checkout page created content: '*/*': schema: $ref: '#/components/schemas/Model761' '401': description: Authentication required content: '*/*': schema: $ref: '#/components/schemas/Model9' '409': description: Resource already exists content: '*/*': schema: $ref: '#/components/schemas/Model566' '500': description: An unexpected error occurred content: '*/*': schema: $ref: '#/components/schemas/Model5' components: schemas: Model759: type: object properties: returnPath: type: string description: >- Path in the web app to come back to afterwards (default `/settings/add-ons`) example: /settings/add-ons maxLength: 200 pattern: ^\/(?!\/) Model761: type: object properties: success: type: boolean example: true data: $ref: '#/components/schemas/Model760' Model9: type: object properties: success: type: boolean description: Always false on errors example: false statusCode: type: number example: 401 error: type: string example: Unauthorized message: type: string example: Authentication required code: type: string description: Machine-readable error code — switch on this, not on message text example: UNAUTHORIZED Model566: type: object properties: success: type: boolean description: Always false on errors example: false statusCode: type: number example: 409 error: type: string example: Conflict message: type: string example: Resource already exists code: type: string description: Machine-readable error code — switch on this, not on message text example: CONFLICT Model5: type: object properties: success: type: boolean description: Always false on errors example: false statusCode: type: number example: 500 error: type: string example: Internal Server Error message: type: string example: An unexpected error occurred code: type: string description: Machine-readable error code — switch on this, not on message text example: INTERNAL_ERROR Model760: type: object properties: url: type: string example: https://checkout.example.com/c/pay/cs_live_a1b2c3 x-format: uri: true ```` ## Related topics - [Turn Market Depth auto-renew off or on](/platform-api/user/turn-market-depth-auto-renew-off-or-on.md) - [Get your Market Depth add-on status](/platform-api/user/get-your-market-depth-add-on-status.md) - [GET /depth/history — rolling order-book depth history.](/market-data-api/historical/get-depthhistory-—-rolling-order-book-depth-history.md) - [Get current ticker prices](/market-data-api/tickers/get-current-ticker-prices.md) - [Submit a market, limit, or stop order](/trade-api/orders/submit-a-market-limit-or-stop-order.md)