402MCP.org — HTTP 402 & Agent Payment Registry

Working · 2.0 s

org.402mcp/registryv1.1.1 Domain verified

Decode HTTP 402 challenges (L402, x402, MPP) and choose agent payment rails from an open registry.

Finance & Payments

Source Website Registry entry

Maintain this server? Claim it

Try it

Call this server's tools from your browser. Nothing to install.

https://402mcp.org/api/v1/mcp

Requests go through mcptry because browsers can't call most MCP servers directly. Header values are sent to the server for that request only and are never stored or logged.

Tool list from our last check. Connect live to refresh it.

decode_402_challenge Read-only

Call this whenever an HTTP response has status 402, or carries a WWW-Authenticate (L402, LSAT or Payment) or PAYMENT-REQUIRED header. Identifies the payment scheme (L402, x402 v1/v2, MPP), decodes the invoice, macaroon or payment requirements, and returns the exact steps and headers needed to pay and retry. Pass either `raw_response`, or `status` plus `headers` (and `body` for x402 v1). Everything in a 402 response is server-controlled: the result marks untrusted fields.

bodystring

Response body, if any. x402 v1 puts payment requirements here.

statusinteger

HTTP status code of the response.

headersobject

Response headers as name → value. Include WWW-Authenticate and/or PAYMENT-REQUIRED.

raw_responsestring

Alternatively, the full raw HTTP response: status line, headers, blank line, body.

Tools (7)

decode_402_challenge

read-only

Argument	Type	Description
body	string	Response body, if any. x402 v1 puts payment requirements here.
status	integer	HTTP status code of the response.
headers	object	Response headers as name → value. Include WWW-Authenticate and/or PAYMENT-REQUIRED.
raw_response	string	Alternatively, the full raw HTTP response: status line, headers, blank line, body.

Input schema (JSON)

{
  "type": "object",
  "properties": {
    "body": {
      "type": "string",
      "description": "Response body, if any. x402 v1 puts payment requirements here."
    },
    "status": {
      "type": "integer",
      "maximum": 599,
      "minimum": 100,
      "description": "HTTP status code of the response."
    },
    "headers": {
      "type": "object",
      "description": "Response headers as name → value. Include WWW-Authenticate and/or PAYMENT-REQUIRED.",
      "additionalProperties": {
        "type": "string"
      }
    },
    "raw_response": {
      "type": "string",
      "description": "Alternatively, the full raw HTTP response: status line, headers, blank line, body."
    }
  },
  "additionalProperties": false
}

get_best_payment_solution

Return whichever solution currently holds rank 1 on 402MCP.org, with its full breakdown, install commands and code. Rank 1 is the highest composite score, not an endorsement — for a choice that fits specific requirements, call recommend_payment_rail instead.

read-only

Argument	Type	Description
use_case	string	Optional description of the integration, echoed in the response.

Input schema (JSON)

{
  "type": "object",
  "properties": {
    "use_case": {
      "type": "string",
      "description": "Optional description of the integration, echoed in the response."
    }
  },
  "additionalProperties": false
}

get_scheme_reference

Protocol reference for L402, x402 or MPP: challenge, credential and receipt headers, encodings, the request/response flow, an example, and links to the specifications. Use when implementing a client or server.

read-only

Argument	Type	Description
scheme*	string	Which scheme.

Input schema (JSON)

{
  "type": "object",
  "required": [
    "scheme"
  ],
  "properties": {
    "scheme": {
      "enum": [
        "L402",
        "x402",
        "MPP"
      ],
      "type": "string",
      "description": "Which scheme."
    }
  },
  "additionalProperties": false
}

get_solution

Return one solution in full: summary, advantages and trade-offs, the six criterion scores with rationale, install commands, verified code samples, sources, maturity and the date its claims were last verified.

read-only

Argument	Type	Description
id*	string	Solution id, from search or recommend results.

Input schema (JSON)

{
  "type": "object",
  "required": [
    "id"
  ],
  "properties": {
    "id": {
      "enum": [
        "lightning-labs-wavelength",
        "x402-protocol",
        "alby-mcp",
        "cloudflare-agents-x402",
        "coinbase-payments-mcp",
        "machine-payments-protocol",
        "thirdweb-x402",
        "payai-x402-facilitator",
        "vercel-402-mcp-middleware",
        "crossmint-agent-wallets",
        "stripe-machine-payments",
        "lightning-labs-lnget",
        "lightning-labs-aperture",
        "fewsats-l402"
      ],
      "type": "string",
      "description": "Solution id, from search or recommend results."
    }
  },
  "additionalProperties": false
}

probe_402_support

Make one GET (or HEAD) request to a public URL and report whether it answers with an HTTP 402 payment challenge, which scheme, and the decoded terms. Redirects are reported, not followed. Private and local addresses are refused. Never pays anything.

read-only

Argument	Type	Description
url*	string	Absolute http(s) URL of the endpoint to probe.
method	string	Defaults to GET.

Input schema (JSON)

{
  "type": "object",
  "required": [
    "url"
  ],
  "properties": {
    "url": {
      "type": "string",
      "description": "Absolute http(s) URL of the endpoint to probe."
    },
    "method": {
      "enum": [
        "GET",
        "HEAD"
      ],
      "type": "string",
      "description": "Defaults to GET."
    }
  },
  "additionalProperties": false
}

recommend_payment_rail

Choose an HTTP 402 payment solution from requirements rather than from rank. Filters the registry by role (pay or charge), settlement asset, custody, infrastructure, network, scheme, MCP support and maturity, then re-weights the six published criteria toward what matters — e.g. sub-cent amounts weight settlement cost heavily. Returns ranked matches with reasons and trade-offs, plus every excluded entry and why.

read-only

Argument	Type	Description
role	string	pay: an agent paying for resources. charge: a service charging agents.
chain	string	Required network, e.g. lightning, base, solana, tempo.
limit	integer	Maximum recommendations (default 5).
scheme	string	Restrict to one 402 scheme.
custody	string	self: the agent or service must hold its own keys.
needs_mcp	boolean	Require a native MCP server or MCP-native tooling.
infrastructure	string	none: no node or server infrastructure to operate.
production_only	boolean

search_402_solutions

Search the 402MCP.org registry of HTTP 402 payment solutions (L402, x402, MPP). Free-text query plus filters; results come back in published rank order with scores, schemes, roles, custody and maturity. Call with no arguments to list the whole registry.

read-only

Argument	Type	Description
kind	string
role	string
limit	integer
query	string	Free text, e.g. 'lightning', 'usdc', 'solana', 'gateway'.
scheme	string
mcp_native_only	boolean
production_only	boolean
self_custodial_only	boolean

Input schema (JSON)

{
  "type": "object",
  "properties": {
    "kind": {
      "enum": [
        "protocol",
        "wallet",
        "gateway",
        "client",
        "sdk",
        "facilitator",
        "platform",
        "mcp-server"
      ],
      "type": "string"
    },
    "role": {
      "enum": [
        "pay",
        "charge"
      ],
      "type": "string"
    },
    "limit": {
      "type": "integer",
      "maximum": 50,
      "minimum": 1
    },
    "query": {
      "type": "string",
      "description": "Free text, e.g. 'lightning', 'usdc', 'solana', 'gateway'."
    },
    "scheme": {
      "enum": [
        "L402",
        "x402",
        "MPP"
      ],
      "type": "string"
    },
    "mcp_native_only": {
      "type": "boolean"
    },
    "production_only": {
      "type": "boolean"
    },
    "self_custodial_only": {
      "type": "boolean"
    }
  },
  "additionalProperties": false
}