iOS App Development
Native Swift and SwiftUI apps that feel at home on iPhone and iPad — built to pass App Store review the first time.
Mobile-first software agency
We build mobile apps
people keep opening.
Appix Engine designs and engineers iOS, Android and Flutter products for startups and scale-ups. One senior team from first wireframe to store launch — and every release after it.
120+ apps shipped
4.9★ average store rating
NDA & IP transfer standard
Built with the tools your own team can maintain
- Swift
- SwiftUI
- Kotlin
- Jetpack Compose
- Flutter
- Node.js
- PostgreSQL
- Firebase
- AWS
What we do
Everything your app needs, under one roof
No handoffs between agencies, no finger-pointing when something breaks. Strategy, design, engineering and release management sit on the same team.
Android App Development
Kotlin and Jetpack Compose builds tuned for the real Android world — mid-range devices, patchy networks, a decade of OS versions.
Flutter Cross-Platform
One codebase, two stores, near-native performance. The fastest route to market when your audience is on both platforms.
UI/UX & Product Design
Research, flows, prototypes and a design system your engineers can actually build — validated with users before a line of code.
Backend & APIs
Auth, payments, realtime sync and push — on infrastructure that stays cheap at 1,000 users and steady at 1,000,000.
Launch, ASO & Growth
Store listings, screenshots, staged rollouts, crash triage and the analytics loop that tells you what to build next.
Appix Engine by the numbers
120+Apps shipped since 2018
18M+Downloads across our builds
4.9★Average store rating
92%Clients who return for v2
Why Appix Engine
Senior engineers. Fixed scope. No surprise invoices.
Most agencies sell you a pitch team and staff the project with juniors. We don't run a bench — the people in your kickoff call are the people writing your code.
- Two-week sprints with a working build at the end of each one. You see progress on a real device, not in a status document.
- You own everything. Source code, repositories, store accounts and design files transfer to you at completion — written into every contract.
- Performance is a requirement, not a phase. Cold-start budgets, frame-time targets and crash-free thresholds are agreed before we start.
- 90 days of post-launch support included. Store rejections, OS updates and hotfixes are covered — not billed back to you.
How a typical engagement runs
Discovery workshop
Two days mapping users, scope and technical constraints. You leave with a spec and a fixed estimate.
Design sprint
Flows, prototype and design system — tested with real users before engineering starts.
Build sprints
Two-week cycles, demo build every Friday, your backlog visible in the same board we work from.
Launch & iterate
Store submission, staged rollout, monitoring — then the next release based on what the data shows.
Selected work
Products we took from idea to store
A sample of recent builds. Full case studies, stacks and outcomes live on the portfolio page.
FreshCart
Grocery delivery for a regional chain — 40-minute slots, live driver tracking and a rebuilt checkout that cut abandonment by a third.
Pulse Fit
Workout tracking with Apple Watch and Wear OS companions, offline-first sync and a coaching layer built on HealthKit data.
Ledger One
A business banking app with biometric auth, instant transfers and SOC 2-aligned audit logging across iOS and Android.
Client feedback
What founders say after launch
“We'd been burned by an offshore team that shipped something we couldn't maintain. Appix Engine rebuilt it in fourteen weeks and handed us a codebase our own hires could pick up on day one.”
“The discovery workshop cut about a third of the features we thought we needed. That decision alone paid for the engagement — we launched two months earlier than planned.”
“Our compliance review is brutal and they cleared it without a single blocking finding. The audit logging they built has since become the reference for our web team.”
Common questions
Before you get in touch
How much does it cost to build a mobile app?
Most of our projects land between $35,000 and $150,000. A focused MVP with one platform and a simple backend sits at the lower end; a multi-platform product with payments, realtime features and compliance work sits at the upper end. After the discovery workshop you get a fixed scope and a fixed price — we don't work on open-ended hourly billing.
How long does development take?
A typical MVP takes 10 to 16 weeks from kickoff to store submission. Larger products run 5 to 8 months. We work in two-week sprints, so you have a running build on a real device from week three onward rather than waiting until the end.
Should I choose native or Flutter?
Choose native when you lean heavily on platform-specific hardware or need the absolute best performance — think camera pipelines, ARKit, or high-frequency background sensors. Choose Flutter when you need both platforms quickly from one team and your feature set is mostly UI, networking and business logic. We'll give you a straight recommendation in discovery, including when Flutter is the wrong answer.
Do I own the source code?
Yes, completely. Repositories, CI configuration, design files and store accounts are yours, transferred at project completion. Full IP assignment is written into every contract, and we sign your NDA before the first technical conversation.
What happens after launch?
Every project includes 90 days of post-launch support covering bug fixes, store rejections and OS compatibility updates. After that most clients move onto a monthly retainer for ongoing features and monitoring, but there's no obligation — if you'd rather take it in-house, we'll run the handover sessions with your team.
Do you work with clients outside the United States?
Yes. Roughly half our clients are in Europe, the UK and the Gulf. We keep at least four hours of daily overlap with your timezone and run all documentation, demos and standups in English.
Have an app idea? Let's pressure-test it.
Book a free 30-minute call. We'll talk through scope, platform choice and a realistic budget — no pitch deck, no obligation.