Finish Missed-Call-to-Booking App

I have a missed-call-to-booking app (Boukkal) that is about 80% built. I need a developer to finish it, fix any bugs, and get it stable enough to run smoothly. The app should be compatible with both Android and iOS platforms. The ideal candidate will have experience in mobile app development and be able to deliver a high-quality, user-friendly application. IMPORTANT: This is a WEB application, not a native iOS/Android app. No Flutter, React Native, mobile push notifications, or app store deployment is needed. Please do not apply if your specialty is mobile app development or UI/UX design only. I have a missed-call-to-booking web app (Boukkal) that is about 80% built and currently hosted on Replit at boukkal.com. I need a backend developer to finish the remaining integration work, fix bugs, and make it stable for a 30-day free trial with real businesses. What it does: when a business misses a phone call, the app sends an automatic SMS via Twilio, an AI (OpenAI/Bland.ai) chats with the caller to gather booking details, books the appointment, and can collect payment through Stripe. Already connected: Twilio (paid account), OpenAI, Bland.ai, Stripe (live mode), email, Google Analytics. A2P 10DLC brand is approved; campaign is being finalized. WHAT I NEED: 1. Finish wiring the new Twilio number (webhooks, TwiML bin, environment variables) 2. Confirm the A2P 10DLC campaign is properly linked once approved 3. Test the full flow end-to-end: missed call → SMS → AI conversation → booking → payment 4. Fix any bugs or broken logic found during testing 5. Migrate hosting from Replit to Railway.app for stability 6. Re-point the boukkal.com domain and webhooks to the new host REQUIRED EXPERIENCE (please only apply if you have actually built, not designed, something using this stack): - Twilio (Voice + SMS + A2P 10DLC compliance) — hands-on, not theoretical - OpenAI API integration - Stripe payments (live mode) - Node.js or Python backend - Experience deploying to Railway.app or similar platforms I have a full technical handover document ready and will share it immediately after hiring, so you can start without back-and-forth. TO APPLY, please answer directly (generic copy-paste proposals will be skipped): 1. Link to a project where YOU personally wrote the backend code involving Twilio or a similar telephony API (not a design mockup or app store listing alone) 2. Your experience with A2P 10DLC specifically, if any 3. Your estimated timeline and whether you prefer fixed price or hourly Realistic scope: this should take an experienced developer roughly 15-25 hours of focused work, not multiple weeks.