> ## 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. # Allocate a payment address > Allocates (or rotates) the temporary payment address for this invoice and returns: - the address to pay, - a quote (estimated token amount + exchange rate), and - a short-lived websocket token for realtime payment updates (`/ws/payment`). Choose `network` and `tokenId` from `GET /api/v1/payments/available-tokens`. ## OpenAPI ````yaml /api-reference/openapi.json post /api/v1/payments/payment-addresses 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/payment-addresses: post: tags: - Payment Sessions summary: Allocate a payment address description: > Allocates (or rotates) the temporary payment address for this invoice and returns: - the address to pay, - a quote (estimated token amount + exchange rate), and - a short-lived websocket token for realtime payment updates (`/ws/payment`). Choose `network` and `tokenId` from `GET /api/v1/payments/available-tokens`. requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/Postapiv1paymentspayment-addressesRequest' example: network: ethereum tokenId: 1 responses: '200': description: Address allocated content: application/json: schema: $ref: >- #/components/schemas/Postapiv1paymentspayment-addressesResponse200 example: temp_address: '0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb' network: ethereum supported_token_id: 1 estimated_token_amount: '100.50' exchange_rate: '0.9950' usd_amount: 100 quote_last_updated_at: 1765540800 quote_valid_until: 1765541100 quote_expires_in_seconds: 300 ws_connection: token: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9... endpoint: /ws/payment format: event_v1 ws_url: /ws/payment?format=event_v1 '400': description: Invalid request or unsupported token/network content: application/json: schema: $ref: '#/components/schemas/Error' examples: invalid_request: value: error: Invalid or missing tokenId code: INVALID_REQUEST_FORMAT wrong_network: value: error: Must complete payment using the same network code: INVALID_PAYMENT_NETWORK wrong_token: value: error: Must complete payment using the same token code: INVALID_PAYMENT_TOKEN '401': description: Missing/invalid session authentication content: application/json: schema: $ref: '#/components/schemas/Error' '404': description: Invoice not found 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 generate payment address content: application/json: schema: $ref: '#/components/schemas/Error' security: - PaymentSessionToken: [] PaymentSessionSignature: [] components: schemas: Postapiv1paymentspayment-addressesRequest: type: object required: - network - tokenId properties: network: type: string description: >- Network identifier from `/api/v1/payments/available-tokens` (lowercase). tokenId: type: integer description: Token identifier from `/api/v1/payments/available-tokens`. Postapiv1paymentspayment-addressesResponse200: type: object properties: success: type: boolean description: Always true; quote availability is communicated via `quote_status`. quote_status: type: string enum: - available - unavailable - expired description: Quote window status for this token selection. status_code: type: string enum: - ok - quote_unavailable - quote_expired - settlement_unavailable description: Machine-readable status. message: type: string nullable: true description: Human-readable status message. temp_address: type: string description: Generated payment address network: type: string description: Network name (lowercase) supported_token_id: type: integer description: Token id that was selected. estimated_token_amount: type: string description: Amount to pay in token (includes buffer) exchange_rate: type: string description: USD to token exchange rate usd_amount: type: number description: Invoice amount in USD quote_last_updated_at: type: integer nullable: true description: Server timestamp the current quote was persisted (epoch seconds). quote_valid_until: type: integer nullable: true description: Server timestamp when the quote expires (epoch seconds). quote_expires_in_seconds: type: integer nullable: true description: Seconds remaining until `quote_valid_until` (computed at send time). retryable: type: boolean nullable: true description: True when the backend recommends retrying to mint/refresh a quote. retry_after_seconds: type: integer nullable: true description: Suggested backoff in seconds when retryable. ws_connection: type: object properties: token: type: string description: >- Short-lived websocket token for `/ws/payment` (treat as sensitive). endpoint: type: string description: WebSocket endpoint path (event_v1 default). format: type: string enum: - event_v1 description: WebSocket payload format (event_v1 only). ws_url: type: string description: WebSocket endpoint with format query (relative path). 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). ````