FAQ

🧭 General

What is Latch?

Latch is an open infrastructure layer for MCP and x402, enabling automatic, on-chain micropayments between AI agents, clients, and APIs. It lets any MCP-compatible app — from ChatGPT to Cursor — pay for tools, models, or services on demand, without subscriptions or API keys.

Do I need to use MCP?

Yes. Latch is built to extend the Model Context Protocol (MCP). Every Latch endpoint follows MCP conventions and adds x402 payment logic as a standardized extension.

Who is Latch for?

  • Developers — Add per-call pricing to APIs, servers, or MCP tools without rewriting infrastructure.

  • Agents / Integrators — Enable autonomous, verifiable payments at runtime using wallets or embedded accounts.

  • Builders — Ship fully paid MCP servers in minutes using the SDK or pre-configured wrappers.

What’s the Latch Registry?

A public index of Latch-enabled MCP servers and their priced tools. It exposes metadata, usage statistics, and direct integration snippets — discoverable from the Explorer.

⚙️ How it works

What is x402 and the 402 flow?

  1. A client calls a protected route or MCP tool.

  2. The service responds with 402 Payment Required and metadata (asset, amount, destination, memo, expiry).

  3. The client (or Latch proxy/SDK) performs an on-chain payment.

  4. The request is retried automatically with the payment proof.

  5. The final response succeeds and streams back to the caller.

This creates a frictionless pay-per-use model directly at the protocol level.

Is it “Stripe for Agents”?

Not exactly. Stripe focuses on traditional human-driven commerce. Latch is built for autonomous, protocol-native transactions — no API keys, no dashboards, just x402 micropayments that agents and apps understand natively.

Can humans also pay?

Yes. Requests from browsers can complete the same x402 flow using wallet extensions or embedded smart wallets — making it seamless for both humans and AI clients.

💰 Pricing & Business

What pricing models are supported?

  • Flat per-call pricing (default)

  • Tiered or per-tool pricing

  • Dynamic pricing (coming soon)

Does Latch take a cut?

No by default. Payments are routed directly to the recipient wallet. Platform fees may apply for optional hosted wallets or advanced analytics services.

Do you support revenue splits?

Yes — splits can be defined in the 402 metadata by specifying multiple destinations. Native multi-recipient support is on the roadmap.

🪙 Payments, Wallets & Chains

Which chains and tokens are supported?

Latch supports stablecoins like USDC or EUROe across multiple networks.

EVM networks: base, base-sepolia, avalanche, avalanche-fuji, polygon, polygon-amoy, iotex, sei, sei-testnet

SVM networks: solana, solana-devnet

What wallets can be used?

  • EOA wallets (private key) for development or automation.

  • CDP / embedded wallets for managed flows.

  • Browser wallets (Phantom, MetaMask, Coinbase) for human requests.

How do I limit spend?

You can set a maxPaymentValue in the SDK (in base units, e.g., 6 decimals for USDC). This enforces per-call or per-session spending caps at the protocol level.

🔒 Security & Reliability

  • No private keys stored. Keys remain on the client or managed wallet provider. Latch only verifies proofs.

  • Built-in rate limiting and caching. The proxy layer applies standard limits, header scrubbing, and GET caching. Additional WAF or throttling is recommended for production.

🧰 SDK, CLI & Developer Experience

What languages are supported?

Official TypeScript SDK + CLI, but any language can integrate by handling 402 Payment Required and returning an X-PAYMENT proof.

How do I integrate quickly?

Using the CLI:

npx latch server --urls https://x402.latchmcp.app/mcp/<id> --private-key 0xYOUR_KEY

How do I define paid tools in code?

Example using the SDK:

import { createMcpPaidHandler } from "latch/handler"

export const paidMcp = createMcpPaidHandler(
  async (server) => {
    server.paidTool(
      "hello",
      "Say hello",
      "$0.001",
      {},
      async () => ({ content: [{ type: "text", text: "Hello, world!" }] })
    )
  },
  {
    recipient: { evm: { address: "0xYOUR_ADDRESS" } }
  }
)

⚖️ Legal

Are you affiliated with APIs or tools wrapped by Latch?

No. Latch is open infrastructure — wrapped APIs remain fully independent and subject to their own policies.

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