In terms of user reach, NEXX4 is the clear leader among the apps I’ve been involved with. It’s available in multiple countries, backed by internet providers, and plays a key role in powering several apps on the App Store.
Another app worth mentioning for its wide adoption is Easy Banking Business. It’s used by all business clients of the bank to handle their operations efficiently.
That said, the app I’d personally consider the most successful, even with fewer users, is NodalView. It’s a startup that’s growing steadily in the competitive real estate sector. What makes it stand out is the innovative use of mobile technology, turning iPhones into essential tools for professionals.
While it may not have the largest user base, its creative approach in a tough market makes it a standout project for me.