# Introduction

The Resolve Partners API is organized around [REST](https://en.wikipedia.org/wiki/Representational_state_transfer) principles.
It uses predictable resource-oriented URLs, standard HTTP verbs and response codes,
and accepts and returns [JSON-encoded](https://www.json.org/json-en.html) request and response bodies.
The Partners API allows you to manage invoices, customers, payouts, and other resources on behalf of your sub-merchants. As a partner (platform or marketplace), you can access and manipulate your sub-merchants' data through this API.
There are two types of partners:
- **Marketplace** — Invoices belong to sub-merchants, while customers belong to the partner (marketplace) itself.
- **Single-merchant** — Both invoices and customers belong to the sub-merchant.

Your partner type determines how certain endpoints behave, particularly regarding the `merchant_id` parameter. See individual endpoint documentation for details.
The current version is **partners-v1**. To upgrade your API version, please reach out to Resolve at [accounts@resolvepay.com](mailto:accounts@resolvepay.com?subject=API%20Version%20Upgrade).