Android and ios Chat App with Back-end Server

We are sourcing for a developer to write an android app with required back-end server codes for a chat mobile application similar to whatsapp/wechat/line. This is a fixed fee project and prior experience on similar apps is required. Please refer to list of key requirements below: - Use of XMPP protocol for chat messaging using text, picture and voice - XMPP client-server code implementation should be clean and shown to be working with server hosted on AWS cloud service, being scalable up to 10,000 users. Evidence of load testing proving scalability is required before delivery is accepted. - Integration with Facebook through FB API for user ID, photo and friends list retrieval. - Geo-location function utilising mobile phone's GPS/WiFi geo-location to do a proximity match of app users - Mobile app will need to incorporate with it the key functions such as, but not limited to, the following: sign-on, log-on, user-profile, user search, geolocation search, active chats, chat management, settings and OS level chat alerts - Message transmission needs to be encrypted/secure and auto secure-delete function of chat contents is needed. - Sufficient API documentation on chat and user related method calls are required. Note that clear documentation is a key deliverable for this project. - All identified bugs will need to be rectified during testing and delivery phase. Payment will be upon delivery of mobile and server app codes that are completely bug free. After project is delivered, we hope to continue working with the same developer on further feature enhancements to this app and also an iOS version, along with app maintenance and support opportunities. Hence, we are seeking a dependable and professional developer to work with.