# API Overview

The OMNO API is a single integration for **Pay-In** and **Pay-Out** across multiple payment providers. This reference is the technical source of truth: authentication, every endpoint, request/response schemas, field tables, cURL and error codes. For flow explanations and when to use each integration, see the [Guides](https://docs.omno.com/guides).

## What the API covers

- **Pay-In** — accept payments (card, APM, crypto).
- **Pay-Out** — send funds to customers, including manual confirm/reject.
- **Cashier sessions** — create hosted checkout sessions.
- **Customers** — create or update customers and their KYC data.
- **Transaction info** — fetch the authoritative status of any transaction.


## Base URL

All API requests go to:

```
https://api.omno.com
```

OMNO provides a single production environment. Testing is done in production with fake PSPs — see the Guides topic [Testing in Production](https://docs.omno.com/guides/getting-started/testing-in-production).

## Authentication

The API uses the OAuth 2.0 **client credentials** flow. Generate a Client ID and Client Secret in the dashboard (Developers → API Credentials), exchange them for an access token at the token endpoint, and send it as `Authorization: Bearer <token>` on every request. See **Authentication** below for the full flow and the token operation.

## API sections

- **Authentication** — obtain an access token (client credentials).
- **Customers** — `POST /public/customer` (create or update a customer).
- **Payments**
  - **Cashier Session** — `POST /public/cashier/session`.
  - **PayIn** — create and process pay-ins.
  - **Payout** — create and process pay-outs.
  - **Confirm / Reject Payout** — approve or reject payouts awaiting manual approval.
  - **Get Transaction Info** — fetch pay-in / pay-out status.
- **PSP** — fetch merchant-enabled PSP configuration.


## Related guides

- [Choose Your Integration](https://docs.omno.com/guides/choose-your-integration)
- [Cashier](https://docs.omno.com/guides/cashier/overview) · [Direct Link](https://docs.omno.com/guides/direct-link/overview) · [Payment Page (Legacy)](https://docs.omno.com/guides/payment-page/notice)
- [Webhooks](https://docs.omno.com/guides/getting-started/webhooks) — the source of truth for final outcomes.


## Support

For technical assistance, contact **support@omno.com**.