Software Engineering
Mobile app development company for iOS, Android, and on-device AI
NextGen Code is a mobile app development company that designs, builds, launches, and maintains iOS and Android apps for businesses and founders. We usually recommend one cross-platform codebase in React Native or Flutter, and we write native Swift or Kotlin when performance or device features call for it.
This is for you if…
- Customers or staff need things a mobile website does poorly: push notifications, the camera, offline access, or one-tap payments.
- You need both iOS and Android but can't fund two separate development teams.
- Your current app crashes, collects poor reviews, or hasn't been updated since the original developer left.
- Apple or Google rejected your app, or you're not sure what store review and privacy rules require.
- Field staff work where the signal drops, so they lose data or re-enter it later.
- You want AI camera, voice, or assistant features without exposing API keys or customer data.
Overview
iOS and Android apps from one codebase, with on-device and cloud AI, built to pass review and stay maintained.
Our app developers in Texas work from Dallas, Austin, Lubbock, and Corpus Christi and have built software for clients since 2018. TownWave runs on web, iOS, and Android from a single codebase; My Patient Express lets clinic patients schedule and wait from home; and DIVIT reads receipts with a vision-parsing algorithm, splits the bill, and requests payment through Venmo.
AI now runs on the phone itself. On-device models handle vision, voice, and text privately and offline, while larger cloud models do the heavy lifting through your backend. We help you decide what runs where based on privacy, cost, speed, and the devices your users actually carry.
What you get
Deliverables, not decks.
- 01
Product and platform plan
User flows, a prioritized feature list, a cross-platform or native recommendation with the reasoning written down, a backend plan, and a checklist of the App Store and Google Play rules your app has to meet, such as in-app account deletion and, if you offer Google or Facebook sign-in, a privacy-focused alternative like Sign in with Apple.
- 02
iOS and Android apps
One codebase in React Native with Expo or in Flutter, or native Swift and Kotlin where warranted. Each app follows its platform's conventions and supports accessibility features such as larger text and screen readers.
- 03
Backend, APIs, and admin dashboard
Sign-in, APIs, push notifications through Apple Push Notification service and Firebase Cloud Messaging, offline sync, and a web dashboard where your staff manage content, users, and orders.
- 04
Payments and subscriptions
Stripe, Apple Pay, and Google Pay for physical goods and real-world services. For digital content and subscriptions, Apple and Google in-app purchases managed through RevenueCat, set up to follow each store's rules, which vary by country and keep changing.
- 05
On-device and cloud AI features
On-device intelligence with Apple's Foundation Models framework, Core ML, and Google's ML Kit, plus cloud models called through your backend. Typical features include camera and vision, voice, and in-app assistants, each with a fallback for older phones.
- 06
Store launch and release pipeline
Developer accounts in your company's name, store listings, Apple's privacy labels and Google Play's Data safety form, TestFlight and Play testing tracks, automated builds, staged rollouts, and crash reporting and analytics from the first beta.
How it works
A clear process, start to finish.
- 012–3 weeks
Discover and decide
We define who the app is for, the jobs it must do, and the features that wait. Then we choose cross-platform or native, plan the backend, and check your idea against store policies before anything gets built.
- 023–4 weeks
Design and prototype
A clickable prototype tested on real phones with real users, designed around iOS and Android conventions, thumb reach, and accessibility.
- 0310–14 weeks
Build and test
Sprints every 2 weeks, each followed by a new TestFlight and Google Play test build, so you use the app as it grows. Automated tests, crash reporting, and analytics are in place from the first build.
- 041–3 weeks
Submit and launch
Store listings, screenshots, privacy disclosures, and review submission, followed by a staged rollout that starts with a small share of users and widens while crash and review data stay healthy.
- 05Ongoing
Maintain and grow
Annual OS updates, SDK and dependency upgrades, store policy changes, and new features driven by analytics and reviews. For apps built with Expo, EAS Update ships JavaScript fixes between store releases, within the stores' rules.
What we measure
The numbers this moves.
We baseline these before we start and report against them after launch.
Crash-free sessions
Tracked in Sentry or Firebase Crashlytics from the first beta build, with a crash-free target agreed before launch and treated as a release blocker.
Activation and retention
The share of installs that finish onboarding, and how many users come back after 1, 7, and 30 days. Those numbers tell you whether the app earns its spot on the home screen.
Time to complete the core task
How long the main job takes, such as booking an appointment or filing an inspection, measured in usability tests and again in production.
Store rating
Average rating and the themes in reviews, watched after every release. In-app review prompts appear after a success, not the moment the app opens.
Time to ship a fix
How long a reported bug takes to reach users. Automated builds, plus over-the-air updates where they apply, target days rather than weeks.
In practice
What this looks like in a real business.
Patient scheduling and intake
My Patient Express gives patients of Community Health Center of Lubbock web and mobile scheduling, profiles, pre-visit questions, and clinic forms, so they can wait from home instead of the lobby.
Camera and vision features
DIVIT reads a receipt through the phone's camera, picks out the line items, tax, and subtotal with a proprietary vision-parsing algorithm, and requests each person's share through Venmo. Today, on-device text recognition paired with a language model can pull structured data from receipts, forms, and labels the same way.
Community and marketplace apps
Grand Car Community connects car enthusiasts through a landing page, a mobile app, and a web app for local meets, forums, and a parts marketplace.
Offline-first field apps
Example: inspectors working in rural West Texas capture checklists, photos, and signatures with no signal. The app writes everything to an on-device database, syncs when a connection returns, resolves conflicts by clear rules, and drafts the inspection summary from photos and voice notes.
Ordering and loyalty apps
Example: a restaurant group's app with mobile ordering, Apple Pay and Google Pay, a points program, and push notifications that send offers based on order history instead of blasting every user.
Voice and assistant features
Example: a hands-free assistant for warehouse staff or drivers that takes spoken status updates, answers questions from the operations manual, and logs everything to the back office.
Tools & platforms we work with
- React Native
- Expo
- Flutter
- Swift
- Kotlin
- Node.js
- Firebase
- Stripe
- RevenueCat
- Sentry
- Core ML
- ML Kit
- TestFlight
- Google Play Console
We're vendor-neutral: we recommend what fits your stack, budget and risk profile — not what pays us a referral fee.
Related work
Built by the same team.
One codebase that put a social music discovery platform on the web, iOS, and Android
TownWave is a social music discovery platform built to give control back to up-and-coming artists. We took it from design concepts and wireframes to a single-codebase product that launched on the web, iOS, and Android.
Web and mobile scheduling that lets clinic patients wait from home
The Community Health Center of Lubbock wanted patients to wait from home instead of in the waiting room. We built a web and mobile system for booking appointments, patient profiles, pre-visit questions, and clinic forms.
A bill-splitting app that reads the receipt and requests each friend's share via Venmo
DIVIT turns a restaurant receipt into a split bill. Its proprietary vision-parsing algorithm reads the receipt, friends are dragged onto the items they ordered, and the app requests each share through Venmo.
Next step
Let's talk about Mobile Apps.
Bring a problem or a goal. In 30 minutes we'll tell you what's realistic, what it would take, and where AI fits — even if the answer is to start smaller.
FAQ
Mobile Apps: common questions
Still have a question? Ask us directly.
How much does it cost to build a mobile app?
Mobile app cost depends on a handful of drivers: whether you need iOS, Android, or both; cross-platform or native code; how much backend work sits behind the app; offline sync; payments or in-app subscriptions; device features such as the camera or Bluetooth; AI features; and the admin tools your staff need. One cross-platform codebase usually costs less than two native apps because most of the code is shared. We scope a first release that proves the app's value and give you a fixed price for it after discovery.
How long does it take to build an iOS and Android app?
A typical first release takes 4–6 months: 2–3 weeks of discovery, 3–4 weeks of design and prototyping, 10–14 weeks of building and testing, and 1–3 weeks for store submission and launch. Leave room for store review, because Apple and Google can reject a build over policy details. Google also requires new personal developer accounts to run a closed test with at least 12 testers for 14 days before launch, one more reason we publish under an organization account in your company's name.
Should we build with React Native, Flutter, or native code?
Choose cross-platform unless you have a specific reason not to. React Native and Flutter both produce fast, native-feeling apps from one codebase, which means one team, one feature set, and features that reach iOS and Android together. React Native suits teams already using TypeScript and React on the web, and Flutter shines with highly custom, animated interfaces. Go native with Swift or Kotlin for heavy AR or 3D, advanced camera or audio processing, deep hardware integration, or an app that only needs one platform.
Who owns the app, the code, and the store listings?
You do. We set up your Apple Developer Program and Google Play Console accounts as organization accounts in your company's name, which requires a D-U-N-S number (a free business ID from Dun & Bradstreet), and add our team as members. The code lives in your repository, signing keys sit in your accounts, and the backend runs in your cloud. If you change developers, you keep the app, its reviews, and its users. Apps published under an agency's account are a common trap that makes switching painful.
Should AI features run on the device or in the cloud?
Use on-device AI when privacy, offline use, or per-request cost matter most, and cloud AI when you need the most capable models. On-device options such as Apple's Foundation Models framework, Core ML, and Google's ML Kit keep data on the phone and cost nothing per request, but the models are smaller and some features need newer phones. Cloud models from OpenAI, Anthropic, or Google are more capable but add latency and usage fees. Cloud calls always go through your backend, so API keys never ship inside the app, and every user gets rate limits and a fallback.
What does app maintenance involve after launch?
Plan for ongoing maintenance, because an app nobody updates eventually breaks or gets blocked from publishing updates. Apple and Google ship major OS releases every year, Apple periodically requires builds made with a recent SDK, and Google Play requires apps to target a recent Android API level. Libraries, payment SDKs, and store policies change too. A maintenance retainer covers OS and SDK updates, dependency upgrades, crash monitoring, store policy changes, and small improvements, with larger features scoped separately.
How do you keep the app secure, and how do you use AI in development?
We build to the OWASP Mobile Application Security Verification Standard (MASVS): no secrets in the app, tokens kept in the phone's secure storage (the iOS Keychain or Android Keystore), encrypted traffic, and server-side checks for anything that matters, because a phone is a device you don't control. AI coding assistants speed up routine work such as tests and boilerplate, but every change gets human code review, automated tests, and dependency scanning before it merges, and we use business-tier tools that don't train on your code.
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