Bug fix and enhancement project for an appointment booking portal

We are looking to experienced and expert level developers to help us fix and enhance an online scheduling/appointment booking system. If you have experience to develop similiar sites like snapappointments or genbook, bookfresh, this may be the right and easy job for you. We require a complete design of a website from start to finish. 1.) Testing and bug fix for including system and functional ones 2.) Enhancement for a few modules (like Paypal payment gateway, Twillo SMS) An ideal potential bidder should have : 1, a demo of your existing scheduling/appointment booking script similar to snapappointments, genbook, bookfresh or similar sites. 2, Proactive working attitude to test, report bugs and provide constructive suggestions for the improvement What we expect you from this project: 1. Delivery time is within 6 weeks after the project is awarded PLEASE BE AWARE THAT WE WILL NOT MAKE UPFRONT PAYMENT AS SO MANY LESSONS WE LEARNT IN THE PAST. WE WILL GO BY FIXED PRICE AND PAY THE WORK THROUGH MILESTONES. Again, please bid this job ONLY if you have already developed the same kind of project in the past and with the know-how in this type of this applications. Kindly send us the demo sites and let's have a quick discussion to move forward. Please also state 'I like coding' as the first sentence in your cover letter, so we know you are serious to our posting. Thanks for reading!