in build.gradle -> android -> defaultConfig write this code: Properties properties = new Properties() properties.load(project.rootProject.file("local.properties").newDataInputStream()) buildConfigField "String", "API_KEY", "\"${properties.getProperty("API_KEY")}\"" in local.properties , write your api key API_KEY=your_api_key and then sync and rebuild project to use, just called BuildConfig.API_KEY