---
title: "Overview"
slug: "overview-3"
updated: 2025-10-23T00:44:24Z
published: 2025-10-23T00:44:24Z
canonical: "developer.upgrade.com/overview-3"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://developer.upgrade.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Overview

## Flex Pay Transaction API

The Flex Pay Transactions API enables you to manage the transaction lifecycle of your orders after your customers have completed the Flex Pay checkout journey. To do so, you will first **authorize** a transaction using the Flex Pay order_id you received from the checkout flow. This will generate a unique transaction_id, with which you can subsequently request payments from Flex Pay by **capturing** the transaction and process refunds to customers by **refunding** the transaction.

At the end of the transaction period, Flex Pay and its lending partners will aggregate all of the period’s transaction events to arrive at a **net disbursement amount** and disburse funds to your designated bank account. Depending on the financial institution’s processing and clearing times, funds will arrive at your bank account within a few business days after the end of the transaction period.

## Integrating Transaction API with Flex Pay BNPL

When using Flex Pay as a payment option an `order_id` is returned from /Orders API. This is true whether you are using our Javascript, Rest API or Mobile SDK solutions. This `order_id` is the key input into the Transaction Authorization API Request.

  

![](https://cdn.document360.io/ff52d920-99b4-4c2b-9b32-5d5fe9700cb0/Images/Documentation/image(24).png)

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