> ## Documentation Index
> Fetch the complete documentation index at: https://next-developers.opencard.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

> Digital receipts for card issuers — match merchant receipts to card transactions via a separate API on receipts.opencard.io.

Give your cardholders **digital receipts** from merchants in OpenCard's network — matched to card transactions and delivered to your callback URL.

This is a **separate product** from the [Issuer transaction API](/card-issuers/issuer-integration) on `api.opencard.io`. Different host, credentials, and use case. You can run one or both.

***

## What you get

| Step        | What happens                                                             |
| ----------- | ------------------------------------------------------------------------ |
| 1. Discover | List merchants (publishers) with active digital receipts and their CAIDs |
| 2. Submit   | POST transaction data for matching                                       |
| 3. Receive  | OpenCard calls your callback when a receipt is found                     |

**Host:** `receipts.opencard.io`\
**Auth:** Bearer JWT (provided at onboarding)

***

## How it fits

```mermaid theme={null}
sequenceDiagram
    participant You as Card Issuer
    participant R as receipts.opencard.io
    participant M as Merchant Network

    You->>R: GET /publishers
    You->>R: POST /callbackrequests
    R->>M: Match receipt
    R->>You: Callback with receipt
```

***

## Guides

| Guide                                                     | What it covers                                        |
| --------------------------------------------------------- | ----------------------------------------------------- |
| [Integration](/card-issuers/digital-receipts/integration) | Step-by-step: publishers, callback requests, clearing |
| [Digital Receipts API](/api-reference/receipts/overview)  | Full endpoint reference                               |

Contact **[support@opencard.io](mailto:support@opencard.io)** for JWT credentials and callback setup.