---
title: "Submit one externally signed Base transaction hash for order-bound verification"
method: POST
path: "/api/v1/orders/{id}/payments/usdc/transactions"
tags: ["Payments"]
---

# Submit one externally signed Base transaction hash for order-bound verification

`POST /api/v1/orders/{id}/payments/usdc/transactions`

## Request

- Base URL: `https://axiomrelay.io`
- URL: `https://axiomrelay.io/api/v1/orders/{id}/payments/usdc/transactions`
- Auth: none declared. Required headers: `X-Axiom-Order-Read-Token`, `Idempotency-Key`

Axiom verifies Base mainnet chain 8453, canonical USDC, payer, recipient, exact amount, payment window, canonical block, finalized head, and global transaction-hash uniqueness before execution. The same transaction can never satisfy two orders.

## Path parameters

- `id` string, required

## Headers

- `X-Axiom-Order-Read-Token` string, required
- `Idempotency-Key` string, required

## Request body

- object
  - `chainId` unknown, required
  - `transactionHash` string, required

## Response `202`

Transaction accepted for observation or synchronously observed

## Other responses

- `409`: Wrong chain, replay, mismatch, or irreconcilable payment evidence
- `503`: Base observer is temporarily unavailable; the durable claim remains retryable

---

[API](https://skmtc.dev/axiomrelay/apis/axiom-relay-control-plane-api.md) · [All operations](https://skmtc.dev/axiomrelay/apis/axiom-relay-control-plane-api/llms.txt) · [OpenAPI document](https://skmtc.dev/axiomrelay/apis/axiom-relay-control-plane-api/revisions/64ba55463cd2?raw)