MCP server · Finance and crypto

402Signal MCP server

Lets your AI check and validate live x402 payment routes before your wallet pays a seller.

402Signal is a checking service for paid API routes that use the x402 payment standard. It looks at an offer, compares it against rules you set, and keeps a signed record of the decision. It is handy if you are building or running an automated buyer that pays for API calls and you want a second set of eyes before money moves.

What is an MCP server? The 30-second version

On its own, your AI can only chat. An MCP server is a small helper program that gives your AI a new skill or a connection to an app or service. This one connects your AI to 402Signal, so it can look up and check x402 payment routes for you. You ask in plain words, and the helper talks to 402Signal on your behalf.

What this MCP server does

You ask your AI to check a payment route or compare a few options. The AI uses this helper, which sends your request to the hosted 402Signal service. The service looks at the current offer, compares it against your budget, networks and rules, and picks from the candidates it checked. You get back a short answer plus a signed record you can keep. Preview and validation are free; a full paid check costs a small amount in USDC.

Flow diagram: you ask your AI “Check if this payment route fits my budget”, the 402Signal MCP server connects it to 402Signal, and you get back short answer and signed record.

Click to zoom

What you can do with it

Check whether a known endpoint's current offer fits your rules
Preview a route before you commit to a paid check
Compare a few candidate services against your budget and allowed networks
Validate a signed record against your original request
Get a signed record you can keep for later review

What it gives back to you

You get a short answer in the chat: whether the offer fits, which candidate was selected, and any reasons it was rejected. When you ask for evidence, you also get a signed record you can save and check later. Preview and validation come back as plain results, and paid checks come back with the record attached.

Before you start

What you need

A 402Signal account and access to the hosted MCP endpoint
An x402-capable HTTP client with payment authority for paid checks
Python 3.12 or later if you use the stdio adapter
A small USDC balance for paid checks (about $0.003 per qualifying check)

Good to know

Paid checks cost a small amount of USDC, and the service does not hold your funds or guarantee that a seller will deliver, so never start a new payment automatically after an unclear result.

Install it with your AI

Add 402Signal MCP server to your AI, no technical skills needed

You don't install anything by hand. You copy one prompt, paste it into an AI that can work on your computer, and it checks, installs and connects the server for you, asking you when it needs something.

Sign in to get the install prompt

Members get a ready-made prompt that lets the Claude desktop app check 402Signal MCP server, install it and connect it for them, step by step. You don't need any technical skills: you copy, paste and answer a few questions. Your connected AI can also find and install any of the 4,066 MCP servers here for you.