ChatGPT Plugin

402MCP

Decode HTTP 402 payments

Brand: 402MCP

Category: Developer Tools
Primary Subcategory: Payment APIs & Integration Development

Integration details

Description

402MCP helps developers and agents work with HTTP 402 Payment Required. When an API answers with a 402, 402MCP identifies the payment scheme (L402, x402 v1/v2 or the Machine Payments Protocol), decodes the invoice, macaroon or payment requirements, and returns the exact steps and header needed to pay and retry. It flags expired challenges, macaroons that do not match their invoice, and every field the server controls. When you are choosing how an agent should pay, or how an API should charge agents, 402MCP recommends a payment rail from your stated requirements (payment size, settlement asset, custody, infrastructure and network) and explains every trade-off and exclusion. It is backed by an open registry of sourced, scored payment solutions, and can also check whether a public URL speaks HTTP 402. Limitations: 402MCP is read-only. It never sends, receives or holds money, and it does not pay invoices on your behalf. Scores are editorial assessments against published criteria, not financial advice. No account is needed.

Integration type: Plugin
Verification status: Not applicable
Platform: ChatGPT
Category: Developer Tools
Primary Subcategory: Payment APIs & Integration Development
Secondary Subcategories: None listed
Brand: 402MCP
Access: No account required
First tracked: 2026-10-30
Tool count: 7
Market: US

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Primary Subcategory

Competing in ChatGPT Payment APIs & Integration Development

View Category

Listed in alphabetical order

Primary Subcategory

402MCPComing soonGet notified

PayFresco Payment PlannerComing soonGet notified

Tools

7 tools agents can invoke

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.
decode_402_challenge
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.
get_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.
get_best_payment_solution
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.
get_scheme_reference
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.
probe_402_support
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.
recommend_payment_rail
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.
search_402_solutions

FAQs

402MCP ChatGPT Plugin FAQ

How the directory, categories and Discoverability Score work.

Read the methodology

How do I improve 402MCP's ChatGPT Plugin discoverability?

The levers are the listing surface agents actually read: names, descriptions, keywords, tool metadata, and registry health. Which lever matters depends on where discovery breaks, which is what continuous measurement shows.

What are 402MCP alternatives on ChatGPT?

As of 2026-10-30, 402MCP competes with PayFresco Payment Planner in ChatGPT Payment APIs & Integration Development, ranked by public Discoverability Score.

Where is this profile measured?

This profile uses the geography attached to the latest public registry snapshot: US. Locale tags are intentionally omitted.