Android/Flutter Mobile App Work/PayPal Gateway Integration

From Bangladesh, India or Pakistan. I need new freelancer for some work of payment method integration at low budget and for long term. , I have a Flutter-based mobile application already live on Android and now need a focused round of development to wire in PayPal as the primary payment gateway. Your task is to create a seamless, production-ready checkout flow that starts inside the app, hands off to PayPal (web view or native SDK—whichever produces the smoother UX), then returns the user to a confirmation screen with robust error handling in place. The integration must: • Support both Sandbox and Live credentials with an easy toggle for me in a config file. • Capture and securely store the PayPal transaction ID, amount, and status, pushing that data to my existing REST back-end endpoint. • Provide callback handling so cancelled or failed payments are correctly surfaced to the user and no stray orders are created. • Remain fully functional on every Android version I currently target (the app ships on Android 10+, though good backward practices are welcome). I will provide: • Current Flutter source, Git access, and back-end API spec. • PayPal REST app credentials for both environments. Acceptance criteria: 1. A test payment in Sandbox mode shows “Payment successful” inside the app and appears in my PayPal dashboard. 2. Cancelling or declining a payment returns gracefully to the previous screen with an explanatory message. 3. Code is pushed via pull request and passes my existing CI pipeline without introducing new issues or warnings. If you spot quick wins—minor UI fixes or performance tweaks—feel free to flag them; I’m open to incremental improvements alongside the gateway work.

Project ID: 40412058