One codebase for iOS, Android and web
Building separate native apps for iOS and Android, plus a web version, multiplies the work and leaves three versions of the product drifting apart. With React Native and Expo, one set of screens, business rules and release process serves every platform. A feature arrives everywhere together, and a fix ships once.
That approach suits most business apps: accounts, dashboards, forms, content, payments and data from connected devices. If your app depends on heavy graphics or deep hardware access, we’ll raise it in discovery and talk through the trade-offs.
What we build
Most mobile products are only as good as the system behind them. We build the app and its backend together, so data, permissions and billing are designed once.
- Consumer and B2B2C apps with a separate experience for each type of user
- Multi-tenant platforms where agencies, teams or clients each see only their own data
- Health, fitness and coaching apps with wearable and activity data
- Subscriptions and payments through Stripe and Affirm
- AI features inside the app, such as AI-assisted analysis with Gemini on Vertex AI
- Real-time features, where users on different devices see the same data update
The backend behind the app
For many apps, Firebase is the right starting point: Firebase Auth for sign-in and Firestore for data that updates in real time, which suits products where two people look at the same record from different devices. Where the app needs heavier processing or its own APIs, we build a Python or Node.js backend alongside it.
Permissions are designed in from the start. In a multi-tenant app every record belongs to a tenant and a role, and what each user sees follows from that. Retrofitting it later costs far more, especially where health or payment data is involved.
Connected devices bring their own work. Wearable data arrives through provider APIs with OAuth tokens that expire, rate limits and webhooks that can fire more than once. We run that sync in the background, so the app stays responsive.
Case studies: ERA Health and NPhase Health
ERA Health’s ERAFit brings training programmes, nutrition, lab results, wearables, CRM and payments into one B2B2C product for agencies, coaches and clients. We built it as a single Expo and React Native codebase for iOS, Android and web, with Firebase Auth and Firestore, Stripe and Affirm billing, and Gemini on Vertex AI for AI-assisted nutrition and lab analysis.
For NPhase Health, we connected consumer wearables such as Fitbit and Strava to research workflows through Terra, with OAuth token refresh, webhook ingestion, background processing on Celery and Redis, and scheduled sync to REDCap Cloud.
Release and after launch
Getting an app approved and into users’ hands is part of the build. We prepare release builds for the App Store and Google Play, set up the web version and plan how updates will reach users once the app is live.
After launch, you’ll want to see crashes, slow screens and failed payments before your users report them. We set up monitoring and hand over the release process, so your team can ship updates. If you’d like us to keep building with you, a retainer is priced on request.
The stack we use
These are the tools we use most for mobile products, all from apps and platforms we’ve shipped.
- App: React Native and Expo for iOS, Android and web
- Backend and data: Firebase Auth, Firestore, Python (Django, Flask) and Node.js
- Payments: Stripe and Affirm
- AI: Gemini on Vertex AI
- Wearables: Terra, with Fitbit and Strava
- Background sync: Celery and Redis
What you get
- A written scope covering users, screens, data, integrations and the release plan
- One React Native app for iOS and Android, plus a web version if you need it
- The backend, sign-in, permissions and payments the app depends on
- Release builds prepared for the App Store and Google Play
- Monitoring for crashes, errors and failed payments
- Test builds you can install and use during the build
- Source code, documentation and a handover of the release process
How it works
1.Discovery and scope
Before the build
An NDA if you need one, then a working session on your users, the journeys that matter most and the systems the app connects to. You get a written scope, architecture and price before any work starts.
2.Prototype the core journeys
Early in the build
Working screens for the most important journeys, on real devices, so you can judge how the app feels before the rest is built around it.
3.Build
Agreed milestones
App and backend built together in working increments, with test builds you can install and use as we go.
4.Release
Before go-live
Testing on iOS and Android devices, monitoring in place, store listings prepared and builds submitted for review.
5.Hand over
At launch
Documentation and a handover of the release process, so your team can ship updates. Ongoing work is available as a retainer, priced on request.
Proof
Story No. 03Healthcare & Fitness
Agencies, coaches and clients on one app that ships to every platform at once
ERA Health
Story No. 08Healthcare & Clinical Research
Clean daily REDCap records from the wearables study participants already own
NPhase Health
“Great working with Waseem, committed and hard worker!”
Price
From£12,000
For a scoped first release of the app and its backend, with test builds throughout and a full handover. Every engagement starts with a free one-hour call, and you get a written scope with a fixed or capped price before any work starts.
FAQ
Our Build Projects start from £12,000 for a scoped first release. The price depends on the number of user types and screens, the backend and integrations the app needs, and whether you want a web version too. You get a written scope and price before any work starts.
For most business apps, React Native is a sound choice: one codebase, one release process and features that reach iOS and Android together. Fully native development can make sense for apps built around heavy graphics or deep hardware access. We’ll tell you in discovery which fits your product.
Yes. With Expo, the same codebase can serve iOS, Android and the web, as it does for ERA Health’s ERAFit. Some screens need a different layout on a large screen, which we plan for in the scope.
Yes. We’ve built wearable integrations for ERA Health and NPhase Health, including Fitbit and Strava through Terra. Each provider has its own permissions, rate limits and sync rules, so we confirm the devices you need during discovery.
Yes. We prepare the release builds and store listings and work through any feedback from Apple or Google. Review times are set by the stores, so we plan launch dates with a margin.