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updatedAt: 2025-06-16T21:19:08.000Z
agentTools:
  projectIndex: https://reference.fidel.uk/llms.txt
---

# Introduction

Welcome to the API Reference of **Select Transactions API**. 👋  You can use this API to implement **loyalty** solutions.

> If you are looking for the API Reference of the **Transaction Stream API** to implement **expense management** solutions,  use [this link](https://transaction-stream.fidel.uk/reference/introduction-1).

The Select Transactions API is organized around REST. **JSON** is returned by all API responses, including errors. In all API requests, you must set the **`content-type`** HTTP header to **`application/json`**. All API requests must be made over HTTPS. Calls made over HTTP will fail.