---
title: "x402 Header Decoder, Payload Linter & 402 Flow Simulator"
method: POST
path: "/v1/tools/decode_x402_payment"
tags: ["x402", "HTTP 402", "stablecoin", "PaymentPayload", "facilitator", "agentic payments"]
---

# x402 Header Decoder, Payload Linter & 402 Flow Simulator

`POST /v1/tools/decode_x402_payment`

## Request

- Base URL: `https://ainumbers.co`
- URL: `https://ainumbers.co/v1/tools/decode_x402_payment`
- Auth: none declared

Decodes x402 PAYMENT-REQUIRED / PAYMENT-SIGNATURE / PAYMENT-RESPONSE headers, lints an exact-scheme PaymentPayload, walks the HTTP-402 request/verify/settle flow, and shows the scheme x network support matrix. exact-scheme authorization sub-fields are illustrative (EIP-3009 style) — verify against the x402 spec.

**Tool URL:** https://ainumbers.co/tools/277-x402-payload-decoder-flow-simulator.html
**AP2/Policy Mandate export:** yes

## Request body

- object
  - `header_or_payload` string, required: A base64 x402 header value or a PaymentPayload JSON.

## Response `200`

Successful tool execution result

- object
  - `decoded` object
  - `findings` unknown[]
    - unknown

---

[API](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite.md) · [All operations](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite/llms.txt) · [OpenAPI document](https://skmtc.dev/ainumbers/apis/ainumbers-co-fintech-intelligence-suite/revisions/b462e4f5bb28?raw)