---
title: "Using the SDK (v4)"
description: "Learn how to use the SDK to interact with Wayflyer's Hosted Capital API"
url: "https://docs.wayflyer.com/embedded-journey-v5-overview/v4-legacy/using-the-sdk"
image: "https://docs.wayflyer.com/_og/d/c_Ocean.takumi,title_Using+the+SDK+(v4),description_Learn+how+to+use+the+SDK+to+interact+with+Wayflyer's+Hosted+Capital+API,props_eyJ0aGVtZSI6eyJtb2RlIjoibGlnaHQiLCJjb2xvcnMiOnsicHJpbWFyeSI6IiMyMzIzMmQifX19,p_Ii9lbWJlZGRlZC1qb3VybmV5LXY1LW92ZXJ2aWV3L3Y0LWxlZ2FjeS91c2luZy10aGUtc2RrIg,s_JWtmSQ3rSre5GQd-.png"
---

## Using the SDK

Learn how to use the SDK package to interact with Wayflyer's Hosted Capital API.

> **This page documents v4 (Hosted Application).** v4 is in maintenance mode. New integrations should use [v5 (Embedded Journey)](https://docs.wayflyer.com/embedded-journey-v5-overview). Existing partners can follow the [Migration Guide](https://docs.wayflyer.com/embedded-journey-v5-overview/migration-guide) to upgrade.

## [Implementation choice](#implementation-choice)

Partners looking for the fastest integration time and lowest maintenance burden should use our UI SDK which provides themeable UI for all call-to-actions.

Partners wishing to develop the UI themselves should use our headless SDK, provides a typesafe wrapper around the Hosted Capital API, providing caching and invalidation for mutations to avoid unnecessary API calls.