Multi-Platform Marketplace App Development

I'm looking for an experienced app developer to create a marketplace app where users can post items for sale. The app needs to be available on both iOS and Android platforms.

Key features include:
- User ratings for sellers
- Payment processing (credit/debit cards and bank transfers)
- Secure funds holding until the buyer receives the item

Ideal Skills and Experience:
- Proven experience in developing marketplace apps
- Strong knowledge of payment integration
- Familiarity with rating systems
- Proficient in both iOS and Android development

Please provide your portfolio and relevant project experience.