# Platforms & Marketplaces

Building with an AI agent? Start at https://docs.payme.io/agents.md

A partner (a platform or marketplace) creates and manages sellers through the API, takes a platform fee on their sales, and pays them out. Partner calls use your `payme_client_key` together with the seller's `seller_payme_id` (MPL). See [Authentication](/payments/getting-started/authentication).

New to this? Start with [Start here: build a platform or marketplace on PayMe](/marketplaces-and-platforms/start-here/how-platforms-work).

## Guides

- [Start here: build a platform or marketplace on PayMe](/marketplaces-and-platforms/start-here/how-platforms-work)
- [Onboard a seller, from creation to first payout](/marketplaces-and-platforms/seller-onboarding/onboard-a-seller)
- [Enable payment methods and services for your sellers](/marketplaces-and-platforms/seller-onboarding/enable-services)
- [Platform fees](/marketplaces-and-platforms/fees-and-payouts/platform-fees)
- [Withdrawals](/marketplaces-and-platforms/fees-and-payouts/withdrawals)
- [Reporting across your sellers](/marketplaces-and-platforms/reporting/reporting-across-your-sellers)

## Default URLs

When PayMe opens your partner account, you give two default URLs:

| URL | Use |
| --- | --- |
| Callback URL | Receives seller and withdrawal callbacks, and the callbacks of sales and subscriptions created without their own callback URL, as `x-www-form-urlencoded` `POST` requests. The full rules are in [Start here: build a platform or marketplace on PayMe](/marketplaces-and-platforms/start-here/how-platforms-work); the payloads are on [Callbacks](/payments/getting-started/callbacks). |
| Return URL | Where PayMe sends the buyer after a successful payment, unless the sale sets its own `sale_return_url`. The redirect is a `GET` request with the sale's parameters. |

## Value-added services

Sellers can have value-added services (VAS), such as invoices, Apple Pay and Google Pay. To turn them on and off, see [Enable payment methods and services for your sellers](/marketplaces-and-platforms/seller-onboarding/enable-services). To see a seller's services, call [List a seller's services](/payments/merchants-management/post-get-vas-seller). The service types are on [VAS types](/marketplaces-and-platforms/seller-reference/vas-types).

## In this group

- [Merchants Management](/payments/merchants-management)
- [Buyers Management](/payments/buyers-management)