# JavaScript Software Development Kit for Freemius

Freemius offers a JavaScript (JS) SDK written in TypeScript to help you integrate Freemius into your SaaS applications. At a glance it has the following features:

* **API Client**: A fully typed API client to interact with the [Freemius API](https://docs.freemius.com/api).
* **Checkout**: Easily create and manage Checkout [options](https://freemius.com/help/help/documentation/checkout/integration/freemius-checkout-buy-button/.md) and [links](https://freemius.com/help/help/documentation/checkout/integration/hosted-checkout/.md) for your application. Also has convenience methods to process redirections from the [Hosted Freemius Checkout](https://freemius.com/help/help/documentation/checkout/integration/hosted-checkout/.md#redirection-after-a-successful-purchase).
* **Webhooks**: Create webhook listeners for specific events and process incoming [webhook requests](https://freemius.com/help/help/documentation/saas/events-webhooks/.md) from Freemius.
* **Pricing**: Easily retrieve data for custom pricing tables within your software.
* **Purchase**: Securely process and manage purchases made through Freemius.

The SDK works for any JavaScript runtime platform including [Node.js](https://nodejs.org/en), [Bun](https://bun.com/), [Deno](https://deno.com/) etc. Please read the guides to get started.

Backend Use Only

The Freemius JS/TS SDK is intended for **backend use only**. It should not be used in frontend or client-side applications (browsers), as it requires access to sensitive credentials such as the Secret Key and Bearer Token. Exposing these credentials in a client-side environment can lead to security vulnerabilities and unauthorized access to your Freemius account.