Hi, there.
I am confident I can full fill your requirement and I provide my skills in hopes of working with you. I am full-time & senior Hybrid(iOS/Android cross-platform) app developer focus on Flutter(DART).
Also I can integrate RESTful APIs, payment gateway(PayPal, Stripe, Google & Apple Pay, WeChat Pay and etc), Social Network API(Facebook, Google, Twitter, Instagram, Pinterest, Youtube and etc), Google Map API and I can implement push notification function and I can approve app on app store or google play store.
I will provide high quality work to you. Please feel free to contact me if you want. I look forward to working back with you. Thank you!