# RevenueCat Documentation — Developer Guides

> Cross-cutting implementation guidance: environment strategies and promotional subscription extensions. Part of the RevenueCat documentation for building in-app purchases and subscriptions.

Each link below points to the Markdown version of a page in this section. For every other section, see the root index at [llms.txt](https://www.revenuecat.com/docs/llms.txt). For the complete documentation as a single Markdown file, see [llms-full.txt](https://www.revenuecat.com/docs/llms-full.txt).

## Developer Guides

- [App Environment Strategies](https://www.revenuecat.com/docs/guides/environment-strategies.md): Strategies for using different environments in your app
- [Promotional Subscription Extensions](https://www.revenuecat.com/docs/guides/promotional-subscription-extensions.md): Automatically extend subscriptions as a promotional offer when customers make a purchase