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

# Integration methods

> Learn about the different ways to integrate with Smile.

There are two main ways to integrate with Smile: by building an app, or using merchant credentials. The right approach depends on your specific use case and requirements. Read on to learn more about each approach and determine which one is right for you.

## Option 1: Build an app

[Building an app](/guides/apps/build) is the recommended approach for cases where the integration is designed to be re-used across multiple accounts. Apps are listed within Smile Admin and installable by any merchant. If you run a SaaS product and want to allow merchants to connect their Smile accounts to your platform, you should build an app.

Right now, Smile's app architecture is well-suited for apps that:

1. Issue rewards for actions that occur in external systems (like leaving a review)
2. Surface rewards information in external systems (like a help desk or ESP platform)
3. Display loyalty information to customers (like their points balance or rewards)
4. Create loyalty accounts for customers

Apps use OAuth for [authorization](/guides/apps/auth/overview), have access to the [REST API](/api/introduction), and can subscribe to [webhooks](/guides/apps/webhooks).

## Option 2: Use merchant credentials

Using merchant credentials is recommended when creating an integration that is specific to a single merchant and not designed to be re-used across multiple accounts.

Merchant credentials provide access to the [REST API](/api/introduction) and [JavaScript SDK](/js/introduction), but cannot subscribe to webhooks.