---
title: "Have I paid this address before?"
method: POST
path: "/api/counterparty/check"
tags: ["verification"]
---

# Have I paid this address before?

`POST /api/counterparty/check`

## Request

- Base URL: `https://api.anygas.xyz/svc`
- URL: `https://api.anygas.xyz/svc/api/counterparty/check`
- Auth: none declared

Address substitution is the most common theft in this space and it is silent — one hex string looks exactly like another. Signed payment requests solve it when the payee cooperates; this covers the other half: an agent about to pay an address it has never paid, with nothing telling it so. Returns YOUR OWN history with the address: times paid, how recently, typical amount, and whether this amount is unusual for that counterparty. IT IS NOT A REPUTATION SCORE. It says nothing about whether the address is honest, and a FAMILIAR ADDRESS IS NOT A SAFE ADDRESS — keys get compromised. A `first-time-recipient` result is not a warning about the recipient either; every legitimate relationship has a first payment. It is the moment to confirm the address by a second channel. READ `coverage`: the float-lane ledger does not retain recipient addresses, so float-lane payouts are excluded and "first time" can be wrong. Surfaced automatically as a WARNING (never a blocker) in /api/preflight/full.

## Request body

- object

## Response `200`

history, signal and explicit limits

- object

## Other responses

- `400`: invalid address

---

[API](https://skmtc.dev/anygas/apis/robyn-anygas-api.md) · [All operations](https://skmtc.dev/anygas/apis/robyn-anygas-api/llms.txt) · [OpenAPI document](https://skmtc.dev/anygas/apis/robyn-anygas-api/revisions/9b7498be8304?raw)