> ## Documentation Index > Fetch the complete documentation index at: https://docs.nuwa.dev/llms.txt > Use this file to discover all available pages before exploring further. # Payment Kit > About Nuwa Payment Kit ## Overview `@nuwa-ai/payment-kit` implements Nuwa's unidirectional payment channels (NIP-4) for HTTP and MCP. It manages channel lifecycle, SubRAV receipts, streaming, and settlement. ## Install ```bash theme={null} pnpm add @nuwa-ai/payment-kit @nuwa-ai/identity-kit @roochnetwork/rooch-sdk ``` ## HTTP Client ### createHttpClient Factory that builds a PaymentChannelHttpClient from an IdentityEnv. **Inputs** Creation options Target service base URL Identity environment Per-request budget (asset base unit) Enable internal logging Custom fetch replacement Persist client state by host Channel meta storage Non-streaming resolve timeout Per-frame idle timeout for streams **Returns** Configured HTTP payer client ### PaymentChannelHttpClient.requestWithPayment Create a payable request and return both response and payment promises. **Inputs** HTTP method Relative URL or path Headers, body, and signal **Returns** Correlation id Raw fetch response promise Resolved payment info (PaymentInfo or undefined) Resolves to object with `data` and `payment` Cancel the request ### PaymentChannelHttpClient.request Convenience wrapper returning only the HTTP response. **Inputs** HTTP method Relative URL or path Request options **Returns** Raw fetch response promise ### PaymentChannelHttpClient.requestAndWaitForPayment Wait for both HTTP response and payment resolution. **Inputs** HTTP method Relative URL or path Request options **Returns** Raw fetch response Payment result (if billed) ### PaymentChannelHttpClient.get/post/put/patch/delete JSON helpers that parse the response and return `{ data, payment }`. **Inputs** Relative URL or path JSON body for POST/PUT/PATCH Request options **Returns** Parsed JSON payload Payment result (if billed) ### PaymentChannelHttpClient.getPendingSubRAV Return the latest unsigned proposal (if any). **Inputs** No input parameters **Returns** Current pending SubRAV ### PaymentChannelHttpClient.getPayerClient Access the low-level payer client. **Inputs** No input parameters **Returns** Low-level client ### PaymentChannelHttpClient.healthCheck Check service health (free). **Inputs** No input parameters **Returns** Server health payload ### PaymentChannelHttpClient.recoverFromService Recover latest SubRAV from service after failures. **Inputs** No input parameters **Returns** Recovery payload ### PaymentChannelHttpClient.logoutCleanup Abort pending requests, reset state, and optionally clear persisted mapping. **Inputs** Delete persisted mapping store Optional note for logs **Returns** No return value ## MCP Client ### PaymentChannelMcpClient (constructor) Create an MCP client with payment channels. MCP server endpoint Per-call budget channelRepo?, namespace? Persist client state Tx logging Fields: enabled?, persist?, maxRecords?, sanitizeRequest? ### PaymentChannelMcpClient.callTool Call an MCP tool; payment handled internally. Tool params Object containing `content: any[]` ### PaymentChannelMcpClient.callToolWithPayment Call a tool and return both business content and payment info. Tool params Correlation id Object with `content` and optional `payment` ### PaymentChannelMcpClient.listTools List server tools with internal reserved params removed. Optional flags (e.g., includeBuiltinTools) Map of tool name to definition ### PaymentChannelMcpClient.tools Return AI SDK compatible ToolSet. ### PaymentChannelMcpClient.listPrompts / loadPrompt Prompt discovery helpers. For loadPrompt Prompt args ### PaymentChannelMcpClient.listResources / listResourceTemplates / readResource Resource discovery helpers. For readResource (string or `uri` object) ### PaymentChannelMcpClient.getPendingSubRAV / commitSubRAV Inspect or commit pending SubRAV. For commitSubRAV Signed subRAV or success marker or null ### PaymentChannelMcpClient.healthCheck / recoverFromService Free endpoints for health and recovery. ### PaymentChannelMcpClient.close / clearPersistedState / getPayerClient / getTransactionStore Lifecycle and accessors. ## Streaming SSE/NDJSON responses include a payment frame that the client extracts and removes transparently. Use the same code paths for streaming and non-streaming.