Check if a package exists on Android Market

For details url and package name (https://play.google.com/store/apps/details?id=com.x.y.z)

Server returns

• HTTP 200: package exists.
• HTTP 404: package does exist

You can perform a simple test on the Android market URL as

https://play.google.com/store/apps/details?id=com.mycompany.myapp

Pass your Application Package name with the letters indented in bold letters in above URL, if you get any result then it is concluded that the Application Package name is already been used, if you get "We're sorry, the requested URL was not found on this server." then you can use the app package name.