As of my last knowledge update in September 2021, I don't have access to real-time data or the ability to provide a current ranking of the top Flutter app development companies. Rankings and reputations of companies in the tech industry can change over time, and it's essential to conduct your research to find the best fit for your specific project requirements.

To identify the top Flutter app development company, you can follow these steps:

  1. Online Research: Start by conducting online research. Look for companies that specialize in Flutter app development.

  2. Portfolio Review: Examine the portfolios of these companies to see if they have experience developing apps similar to your project. This will help you assess their capabilities.

  3. Client Reviews: Read client reviews and testimonials to get insights into their past clients' experiences. This can provide valuable information about their communication, project management, and overall performance.

  4. Industry Recognition: Companies that have received awards, certifications, or recognition within the app development industry may be indicative of their expertise and quality of work.

  5. Consultations: Reach out to multiple companies for consultations. Discuss your project requirements, budget, and timeline. This will also give you a sense of their responsiveness and communication skills.

  6. References: Ask for references from the companies and contact past clients to inquire about their experiences working with the company.

  7. Budget Considerations: Ensure that the company's pricing aligns with your budget. Request detailed quotes and consider any additional costs that may arise during the project.

  8. Location: Decide whether you prefer a local development team or are open to working with remote companies. Many top Flutter development companies offer remote services, which can be cost-effective.

  9. Development Process: Understand the company's development process, including project management practices, communication channels, and quality assurance procedures.

  10. Post-launch Support: Inquire about post-launch support and maintenance services to ensure your app remains up to date and functional after deployment.