Senior App Developer

Zenzero is one of the UK's fastest-growing technology companies. Named a Top 8 Technology Company at the British Business Awards 2026, recognised by Deloitte as a Best Managed Company, and featured in the Sunday Times Hundred (an annual ranking of the UK's fastest-growing private companies) in both 2025 and 2026, we hold Microsoft Solutions Partner status across all six designations, putting us in the top tier of UK Microsoft partners. The accolades reflect something real: a business that is scaling fast, executing well, and building something that lasts. We're on a mission to make technology genuinely work for mid-market businesses, covering managed IT, cyber security, cloud, and AI solutions that actually move the needle. The demand is growing, and so are we. We're also a certified B Corp and Scale Up Award winner. That combination matters to us: high growth and high standards aren't in conflict here. Fast growth, high standards, real impact. If that sounds like your kind of place, keep reading. Minimum 5 years commercial development experience Flutter / Dart — strong commercial experience building cross-platform mobile apps iOS and Android development principles and deployment processes Experience working with legacy app development technologies and codebase migration RESTful API design and integration Version control (Git) and collaborative development workflows Strong communication skills — comfortable dealing directly with clients Lead the design, development and delivery of mobile and cross-platform applications Act as the primary technical authority for app development within the DDS team Work with clients and internal stakeholders to understand requirements and deliver solutions Maintain and modernise legacy application codebases where required Mentor junior and mid-level developers on app development best practices Contribute to technical planning, estimation and architecture decisions Desirable: Native iOS (Swift) or Android (Kotlin / Java) development CI/CD pipelines and mobile app deployment (App Store / Play Store) Microsoft Azure or other cloud platforms UX/UI principles for mobile applications Private health insurance Generous holiday allowance + a day off on your birthday Flexible working patterns Enhanced pension contributions Regular social events across all our offices