---
title: "The transaction that tops up a key"
method: GET
path: "/v1/topup"
---

# The transaction that tops up a key

`GET /v1/topup`

## Request

- Base URL: `https://qmax.exchange/api`
- URL: `https://qmax.exchange/api/v1/topup`
- Auth: none declared

Returns a transaction to sign and broadcast from any wallet: send `amountQu` QU to QPayhub (contract index 29) with inputType 1 and the given base64 payload, which is Pay(seller, resourceId, nonce). QPayhub forwards the payment to QMax and records a receipt that names the key. Then call POST /v1/topup/claim. Amounts below minTopupQu are refused because QPayhub keeps at least 100 QU of every payment.

## Query parameters

- `keyId` string, required
- `amountQu` integer, required
- `nonce` string

## Response `200`

{ contractIndex, inputType, amountQu, payload, nonce }

---

[API](https://skmtc.dev/qmax/apis/qmax-api.md) · [All operations](https://skmtc.dev/qmax/apis/qmax-api/llms.txt) · [OpenAPI document](https://skmtc.dev/qmax/apis/qmax-api/revisions/af70e2813a7a?raw)