Mobile App Development
Smarter workflows, cleaner interfaces. Custom iOS and Android apps designed to perform and built to last.
Built a research tool exploring how grocery apps like Tesco and Just Eat can nudge shoppers towards healthier choices.
Created an intuitive community app designed to bring people together through shared activities and real-world connections.
Designed and built the free period tracker app paired with their sustainability-first menstrual cup.
Building out the mobile apps behind their patient insight platform for the pharma industry.
Built the coach-and-athlete app that integrates with wearables to deliver live training data, from heart rate to pace.
Long-term innovation partner, with our team embedded alongside theirs on the digital community platform connecting veterans, serving soldiers and their families.
Built a mobile app bringing Mixcloud livestreaming and audio editing to Evermix's recording artists.
Built the mobile marketplace where musicians, engineers and studios find, book and showcase recording services.
Took over development of Molehill Mountain, their app helping autistic people manage anxiety and stress.
Overview
We pair AI-assisted prototyping with rigorous, human-led engineering to build iOS and Android apps that scale. And we're straight about cost and timeline from the first conversation.
Old.St Labs is an app development company based in London, working with clients across the UK and US. We build cross-platform mobile products for startups bringing an idea to life and for established businesses that need a tool the market doesn't sell. By weaving AI tools into our day-to-day workflow, we strip out the usual development headaches and keep projects moving quickly without cutting corners. The result: smooth, secure apps your users will love.
Partnering with Old.St Labs
Why choose Old.St Labs for mobile app development?
Business Tools & Custom Apps
The app your business actually needs, not the SaaS that nearly fits.
We build custom mobile tools for established businesses, from apps for teams in the field and customer-facing products to mobile front-ends for the systems you already run. If spreadsheets, workarounds or off-the-shelf software are holding your team back, we build around the way your business actually works.
MVP & Startup Builds
From concept to live app, kept lean.
Founded to support ambitious creators and scale-ups, we speak fluent founder. We skip the usual agency overhead to build and launch focused, production-ready MVPs in 8 to 12 weeks, putting your product in front of real users faster.
Interactive Prototyping Before Production
Validate with real users in days, not months.
Before we write production code, we turn your idea into a high-fidelity interactive prototype you can click through, test and put in front of real users. It is a faster, cheaper way to validate the experience and resolve the big product decisions before development begins.
Cross-Platform Efficiency
One codebase. Two platforms. No compromise on quality.
We specialise in React Native, allowing us to build high-quality iOS and Android apps from a single codebase. That means less duplicated development, easier maintenance and a budget that goes further. We can integrate native device features such as biometrics, cameras and notifications, and we build with App Store and Google Play requirements in mind from day one.
AI-Powered Mobile Applications
Build AI into the places where it actually adds value.
We integrate AI where it makes the product genuinely better, whether that is intelligent assistants, personalised experiences, voice interfaces, search or automation. We also use AI throughout our own development process to work faster, reduce repetitive effort and deliver high-quality software more efficiently.
Mobile Development Lifecycle
How we take your mobile app from idea to launch
01
Definition & Mobile Strategy
We define what your users need to do on mobile, where the app fits into your wider product or business, and which features belong in the first release. We also make the early technical decisions, including iOS and Android requirements, cross-platform versus native development, integrations and device capabilities.
02
Mobile UX & Prototyping
Mobile products need to feel intuitive in the hand, not just look good on a screen. We design around real mobile behaviours, from navigation and gestures to permissions, notifications and different screen sizes, then turn the experience into an interactive prototype you can test before development begins.
03
App Development & Integration
We build the app, connect it securely to your backend systems and integrate the mobile features your product needs, from biometrics and cameras to push notifications, payments and AI. We test across devices and operating systems throughout development, with regular builds and clear progress reporting.
04
App Store Launch & Evolution
We prepare your app for Apple and Google submission, handle the release process and support you through review and launch. Once live, we can monitor performance, respond to OS updates and continue improving the product based on real user behaviour and feedback.
Case studies
Mobile products brought to life
Asan
Period tracker mobile app to track period dates, give insights about all phases of the period cycle, and tracks period product carbon impact.
The Military App
Creation of a social platform for current and former Military personnel.
Pickr
Launched a music industry marketplace app connecting studios, engineers, and session musicians.
Allegr
Creation of a social connecting app to help support communities.
CityMunch
Creation of a real-time offer app for food discovery.
Tech stacks
Proven tools for building fast, secure and scalable mobile apps
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.
Engineering & AI Stack
Design & prototyping
Engineering & AI Stack
Engineering & AI Stack
Design & prototyping
Engineering & AI Stack
Cloud & Infrastructure
Design & prototyping
Engineering & AI Stack
Engineering & AI Stack
Engineering & AI Stack
.svg){kind=logo}
Engineering & AI Stack
Engineering & AI Stack
Engineering & AI Stack
Engineering & AI Stack
Cloud & Infrastructure
Engineering & AI Stack
Collaboration & Management
Testimonials
What our clients say about building with us. From first idea to launch and beyond, our clients share what it’s like to work with Old.St Labs and the impact our products have had on their businesses
FAQs
Got questions? We've got answers.
Everything you need to know about how we build, ship, and partner with you
Does Old.St Labs build iOS and Android apps?
Yes. We build custom iOS and Android apps from a single React Native codebase, so one build covers both platforms. We handle everything from scoping and design through to App Store and Google Play launch, and we stay involved after release as your product innovation partner.
How much does mobile app development cost in the UK?
Most mobile apps we build fall between £10,000 and £100,000, depending on scope, integrations and design complexity. Because we build iOS and Android from one codebase, you're not paying twice for two platforms. We also work with US clients and can quote in dollars. Every project starts with a scoping phase, so you'll know the full cost before production work begins.
How long does it take to build a mobile app?
A production-ready MVP typically takes 6 to 12 weeks. You'll have an interactive prototype to test much sooner, before any production code is written. Larger products with complex integrations take longer, and we'll give you a realistic timeline during scoping rather than a hopeful one.
Can Old.St Labs add AI features to a mobile app?
Yes. Around a dozen of the 60+ products we've delivered include AI components, from in-app assistants to personalised content and automation. We'll tell you straight where AI adds real value in your app and where it doesn't, then build the features that earn their place.
Does Old.St Labs publish apps to the App Store and Google Play?
Yes. We handle the full submission process for both stores: developer accounts, certificates, review guidelines, store listings and release management. After launch we monitor performance and ship updates, so your app stays healthy well beyond day one.
Can Old.St Labs take over an existing app or prototype?
Yes. We regularly take over apps started elsewhere, including prototypes built with AI tools like Lovable, Replit or Cursor. We start with a technical review of what's salvageable, then either productionise your existing code or rebuild it properly, whichever gets you to a secure, scalable product faster.
Should I build a native app or a cross-platform app?
For most products, cross-platform is the right answer: React Native gives you native-quality iOS and Android apps from one codebase, at a significantly lower cost than building each separately. Fully native development only earns its premium in edge cases like graphics-heavy games. We'll tell you honestly if your product is one of them.
Do I need a technical background to work with Old.St Labs?
No, and you're in good company: both our founders come from non-technical backgrounds. The whole process runs in plain English, from scoping through to launch. We do the translating; you make the decisions.
Services
Explore our full suite of product capabilities. We build connected digital ecosystems that drive growth across every screen
Mobile App Development
High-performance iOS and Android apps built for scale
AI Solutions
Smart automation and LLM integration to supercharge your workflow
UI/UX Design & Prototyping
High-fidelity designs and interactive prototypes users love
Web App Development
Web applications built around how your business runs.
Contacts
Let's talk
High-quality results, delivered fast by a team you trust
Rob Lynch
Co-Founder
After starting his career in banking and renewable energy investment, Cambridge Master of Finance graduate Rob L. founded CityMunch in 2016, an award-winning restaurant deal app that raised two rounds on Seedrs and reached 100,000 users.
Rob Woodhead
Co-Founder
Rob co-created EV Technology in 2017, an award-winning business helping vehicle fleets transition to electric, after an initial career in corporate finance and private equity across London and New York. He co-founded Old.St Labs to be the development partner he wished he'd had as a non-technical founder.
