Difference of using api or implementation in Android dependencies in Gradle

^{Something similar to yours 1} happened to me , so I was reading the Use the new dependency configurations section of the Android documentation.

There they explain the difference (bold is mine):

implementation

The dependency is available at compile time to the module and only at runtime to the module's consumer. For large builds that span multiple projects, using implementationinstead of apior compilecan lead to significant build-time improvements by reducing the number of projects that the build system must recompile. Most app and test modules should use this setting .

api

The dependency is available to the module at compile time, and is also available to the module's consumer at compile time and at run time. This setting has the same behavior as compile(which is now deprecated) and should normally be used only in library modules . App modules should use implementation, unless you want to expose their API to another test module.

As is the case with the current stable versions of the Android plugin, the above configurations are available for dependencies on specific classes or build types. For example, you can use apito make the dependency available to all variants, or redApito make it available only to network variants of the module.

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And finally, a note:

Note: compile, providedand apkare still available. However, they will be gone in the next major version of the Android plugin.

¹ _{Related question: How to apply the new Android Studio dependency settings?}