> ## Documentation Index > Fetch the complete documentation index at: https://docs-alpha.pepay.io/llms.txt > Use this file to discover all available pages before exploring further. # Submit form responses > Submit responses to invoice custom questions (see `GET /api/v1/payments/invoice-questions`). ## OpenAPI ````yaml /api-reference/openapi.json post /api/v1/payments/submit-form openapi: 3.0.0 info: title: Pepay API (SDK-scoped) version: 1.0.0 description: API documentation for Pepay API servers: - url: https://api-beta.pepay.io description: Beta server - url: http://localhost:3000 description: Local development security: - bearerAuth: [] tags: - name: Events description: Events API (history + debugging) for canonical notification envelopes. - name: Metrics description: Internal Prometheus metrics (restricted). - name: WebSockets description: WebSocket streams (upgrade endpoints) and message schemas. - name: Commerce - Devnet Simulator description: > Deterministic devnet-only endpoints for simulating Commerce V2 order state transitions. Use this when integrating as a merchant on devnet to test your backend/UI against realistic order lifecycle changes (payment confirmation, settlement gating, placement, tracking, cancellation, refunds) without placing real retailer orders or sending real on-chain refunds. How it works: - Requires a devnet `X-Commerce-Api-Key` (merchant-scoped). - Only operates on orders created in `networkEnvironment=devnet`. - Updates the order using the same reducer/persistence paths used in mainnet (provider snapshots are simulated). - After each simulation, Pepay emits the normal `commerce.order.updated` merchant webhook event. - name: Merchant Checkout description: > Merchant-scoped **three-step** checkout flow: 1) `POST /api/commerce/merchant/checkout/estimate` — validate items against current eligible offers and return `validItems[]` + `invalidItems[]`. 2) `POST /api/commerce/merchant/checkout/address` — attach and validate a shipping address for the estimate. 3) `POST /api/commerce/merchant/checkout/invoice` — create the final invoice + commerce order. Cart behavior (when `useCart: true`): - The estimate call **reads** the saved cart but does **not** remove or modify cart items. - Items with no eligible offers are returned in `invalidItems[]`. - To remove items from the saved cart, call the Merchant Cart APIs (`PUT /api/commerce/merchant/carts/items/:itemId` with `quantity: 0`, or `DELETE /api/commerce/merchant/carts/items/:itemId`). - To exclude items for *this checkout attempt* without mutating the cart, use `itemOverrides[]` with `quantity: 0`. - name: Payment Sessions description: > Payor-facing APIs used by the hosted payment page and other embedded checkout clients. Canonical base path: - All documented endpoints are under `/api/v1/payments/*`. Authentication: - These endpoints do **not** accept merchant API keys or bearer JWTs. - Send `x-session-token` and `x-signature` headers on every request (both are returned when creating an invoice). Typical flow: 1) Create an invoice (`POST /api/v1/invoices`) → receive `payment_url`, `session_token`, `signature`. 2) Render/open the `payment_url` for the payor. 3) Fetch invoice context (`GET /api/v1/payments/session-details`). 4) List supported tokens (`GET /api/v1/payments/available-tokens`). 5) Allocate a payment address (`POST /api/v1/payments/payment-addresses`) → use `ws_connection` for `/ws/payment`. 6) Track progress via polling (`GET /api/v1/payments/payment-status`) and/or websocket (`/ws/payment`). Security notes: - Treat `session_token` and `signature` as sensitive values (anyone with them can read the invoice/payment status). - Do not store them in long-lived browser storage; prefer in-memory usage on the payment page. - name: Quotes description: Token settlement quotes and rate calculations - name: Webhooks description: > Webhook endpoint management and delivery history for canonical notifications. Delivery model: - At-least-once delivery; receivers must dedupe by `event.id` (also sent as `X-Pepay-Event-ID`). - Payloads are canonical `PepayEvent` objects and match websocket `event_v1` frames for the same event type. Security: - Endpoints must be HTTPS. - Deliveries are signed using `HMAC_SHA256("${timestamp_ms}.${raw_body}")` and sent in `X-Pepay-Signature`. paths: /api/v1/payments/submit-form: post: tags: - Payment Sessions summary: Submit form responses description: >- Submit responses to invoice custom questions (see `GET /api/v1/payments/invoice-questions`). requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/Postapiv1paymentssubmit-formRequest' example: responses: - question_id: q1 response: customer@example.com - question_id: q2 response: Acme Inc responses: '200': description: Responses submitted successfully content: application/json: schema: $ref: '#/components/schemas/Postapiv1paymentssubmit-formResponse200' example: success: true '400': description: Invalid responses or no questions found content: application/json: schema: $ref: '#/components/schemas/Error' '401': description: Missing/invalid session authentication content: application/json: schema: $ref: '#/components/schemas/Error' '410': description: Invoice has expired content: application/json: schema: $ref: '#/components/schemas/Error' '429': description: Too many requests content: application/json: schema: $ref: '#/components/schemas/RateLimitError' '500': description: Failed to submit form responses content: application/json: schema: $ref: '#/components/schemas/Error' security: - PaymentSessionToken: [] PaymentSessionSignature: [] components: schemas: Postapiv1paymentssubmit-formRequest: type: object additionalProperties: false required: - responses properties: responses: type: array minItems: 1 maxItems: 5 description: List of responses keyed by question id. items: type: object additionalProperties: false required: - question_id - response properties: question_id: type: string pattern: ^q[1-5]$ response: oneOf: - type: string - type: number Postapiv1paymentssubmit-formResponse200: type: object properties: success: type: boolean Error: type: object description: Standard error response (not used for rate limiting). properties: error: type: string description: Human-readable error message. code: type: string nullable: true description: Optional machine-readable error code. details: nullable: true description: >- Optional structured details (present in some development/debug scenarios). oneOf: - type: string - type: object additionalProperties: true - type: array items: type: object additionalProperties: true example: error: Failed to fetch available tokens code: DATABASE_ERROR RateLimitError: type: object description: Rate limit error response (HTTP 429). properties: error: type: string error_code: type: string source: type: string example: error: Too many requests. Please try again in a minute. error_code: PAYMENT_SESSION_RATE_LIMIT source: payment_session securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: JWT description: JWT token for wallet authentication PaymentSessionToken: type: apiKey in: header name: x-session-token description: >- Payment session token (opaque). Returned when creating an invoice; send on every request. PaymentSessionSignature: type: apiKey in: header name: x-signature description: >- Payment session signature in the format `signature_hash.timestamp_ms` (returned with the invoice/session). ````