I'm planning to create an offline music app for iPhone and need some recommendations for reliable iOS application development services. I'm looking for a development company or a team of experts that has a proven track record in building robust music apps with offline capabilities. If you have any suggestions or know of companies that specialize in this type of project, I'd love to hear about your experiences. What should I look for when choosing a development partner for a music app, and what questions should I ask to ensure they understand the requirements for offline functionality?

Additionally, I'd like to know which free music apps for iPhone offline you find most useful. What features do these apps offer that make them stand out? If you've used or developed similar apps, I'd appreciate any insights into what makes a successful offline music app for iOS. Any tips or best practices on building a seamless user experience with offline music would be greatly appreciated. Thanks in advance for your suggestions and advice!