Dear sir
I read your job description carefully and I think I’m very qualified for your project.
I’m Android Senior Developer.
I have rich experience of android app develop for 7 years,
your project need back-end web service API.
So, app can communicate with your server using API.
I have full experience of RESTful json based back-end Web service API develop.
I can do it perfectly and no problem,
If you select me, I will show you my best skill and my effects.
I can deliver high-quality result to you, fast turnaround time.
Thank you for the opportunity to submit my proposal for your project.
Best regards.