From the API Guidelines:
You cannot replicate the core user experience of Unsplash (unofficial clients, wallpaper applications, etc.).
The best way to make sure that your application doesn’t violate this guideline is to integrate Unsplash inside an existing app that offers more value than simply the Unsplash integration.
Some examples:
✅ the Ghost integration brings Unsplash inside Ghost’s editor to improve the workflow of finding beautiful images. Without the integration, the app still has a lot of value to its users.
✅ the Trello integration brings Unsplash images inside Trello's productivity app to allow uses to customize the backgrounds of their boards. Without the integration, the app still has a lot of value to its users.
✅ the Medium integration allows writers to include Unsplash images with their posts. Without the integration, the app still has a lot of value to its users.
🚫 a wallpaper app returns Unsplash images for downloading. Without the integration, the app has no content and no value to users.
🚫 an unofficial Unsplash for Android app allows users to search for Unsplash images and download them. Without the API, the app has no content and no value to users.
If you think your usage might conflict, shoot us an email before you integrate and we can let you know ahead of time.
We’re all for remixing and open-source, but the API costs us a non-trivial amount of money to host, operate, and provide support for. There are thousands of interesting and valid ways to use the Unsplash API that provide additional value to the community and users, so we prefer to focus the API on supporting those experiences.