---
title: "Overview"
slug: "ios-overview"
updated: 2026-06-24T13:57:26Z
published: 2026-06-24T13:57:26Z
canonical: "developer.upgrade.com/ios-overview"
---

> ## 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

### Overview

**Flex Pay's iOS SDK** provides partners with the means to rapidly integrate Pay Monthly travel lending functionality into their iOS application

Flex Pay defines three phases of the consumer experience:

- Shop
- Checkout
- Confirmation.

During the **shop phase**, the presence of Pay Monthly messaging (or PM Messaging) drives awareness of the pay-over-time option, which in turn leads to higher conversion and increased cart size.

At **checkout phase**, a fully embedded application flow contained within Flex Pay's secure flow ensures that sensitive customer information is continuously safeguarded.

The **confirmation phase** is any activity after a booking transaction occurs.

This document details the manner in which all partners can use Flex Pay's iOS SDK to seamlessly integrate Pay Monthly into their application.