You don’t need apply plugin: 'io.fabric' in your build.gradle script in order to user Crashlytics error reporting or Answers.

You need only provide your Fabric API key as an android resource. You also need to disable Crashlytics’ build ID requirement; without the plugin, you won’t generate a Crashlytics build ID.

There are two easy ways to set these resources.

You can put these lines in your build.gradle:

resValue "string", "io.fabric.ApiKey", YOUR_FABRIC_API_KEY
resValue "bool", "com.crashlytics.RequireBuildId", "false"

Or you can put these lines somewhere in res/values:

<string name="io.fabric.ApiKey">YOUR_FABRIC_API_KEY</string>
<string name="com.crashlytics.RequireBuildId">false</string>

That’s it; now you can use Crashlytics as usual.

repositories {
    maven { url '' }
dependencies {
    compile('') {
        transitive = true
Fabric.with(this, new Crashlytics());

This works with Crashlytics error reporting and Answers; I haven’t tested with “Crashlytics Beta”.