Mobile App Development in London, USA

Mobile App Development in London, USA — Mobile development that converts London users into customers

Today, having production mobile applications isn't enough for a London business. Your potential client opens a smartphone on the Victoria line, sees three or four similar offers, and decides in 5 seconds which one to engage. If yours is slow, unclear on mobile, or doesn't render correctly under iOS Safari with intermittent the Tube connectivity — you've lost that customer before they finished reading your headline. That's why investing in quality Mobile development isn't a "luxury expense", it's a direct investment in revenue.

I'm Alex Filiuk, a Senior practitioner with 15 years of experience and a portfolio of 130+ projects. I deliver production mobile applications for businesses in London, across the US (San Francisco, LA, Boston, Austin), in Europe (London, Manchester, Edinburgh), and in Ukraine. On this page I've collected what's worth knowing for an London business owner before commissioning mobile development: how the engagement works, USD pricing brackets, which mistakes destroy ROI, and which 2025-2026 trends actually matter for the London market.

Why mobile-app development matters for London businesses

For London consumer brands, mobile is not 'one of the channels' — it's the channel. 75–85% of consumer engagement happens on mobile. App-store ranking, push-notification engagement, biometric auth, Apple Pay / Google Pay, native-camera workflows, ARKit / ARCore experiences — all live on mobile. A web app wrapped in a WebView won't compete with native or properly-built React Native; consumer London users rate-down apps that feel 'web-stuck' within minutes of install.

What quality mobile-app development delivers for an London business:

• Native-feel engagement. Properly built React Native or fully native iOS / Android apps deliver 60-fps animations, sub-100ms responsiveness — direct retention impact.
• Platform-native integrations. Apple Pay, Google Pay, biometric auth, ARKit / ARCore, HealthKit, native push — surfaced as primary, not as fallbacks.
• Code reuse via React Native or Expo. 70–85% code shared across iOS / Android — half the engineering cost of two fully native builds.
• Production-grade ops. CI/CD with EAS Build / Bitrise / Fastlane, crash reporting (Sentry / Bugsnag), feature flags, OTA updates via CodePush / EAS Update.
• Store-submission expertise. Apple App Store + Google Play submission packages prepared correctly first-pass — rejection rates near zero.

Mobile-app development vs the templated approach

Naive mobile development is 'wrap the website in a WebView' or 'build a quick React Native MVP and ship'. Both produce apps that work for the first 1,000 users and fall over at scale. Production-grade mobile development covers performance, observability, OTA update strategy, crash management, and store-submission compliance from day one.

A real London-grade mobile build covers:

• Tech-stack decision. React Native + Expo for most consumer apps; fully native (Swift / Kotlin) for performance-critical (AR, video, real-time) workloads.
• State management and data layer. TanStack Query / Zustand / Redux Toolkit / Apollo — chosen for the data shape, not by default.
• Native modules where needed. Custom Swift / Kotlin modules for hardware-specific features (camera, biometrics, AR, HealthKit) bridged correctly.
• Push, deep-link, and OTA-update infrastructure. APNs / FCM, universal / app links, CodePush / EAS Update — production-ready, not 'we'll figure it out'.
• Observability and crash management. Sentry / Bugsnag, structured logs, feature flags (LaunchDarkly / GrowthBook) for safe rollouts.

Mobile development is most effective when paired with mobile-app design and a strong backend — see CRM/ERP/SaaS development for the data and admin layer.

Project types most-requested by London clients

Across 15 years and 130+ projects, I've noticed London business categories have their own digital signature. Most-common requests for mobile-app development:

• Fintech consumer apps. Shoreditch / City of London fintech building investment, payments, crypto apps with Plaid / Stripe Identity / KYC flows, biometric auth.
• Healthcare apps. London clinics and wellness startups building HIPAA-compliant patient apps, telehealth video, secure messaging.
• Marketplace and on-demand. Shoreditch / the City of London on-demand services (delivery, home services) with dual-sided React Native apps.
• DTC commerce companion apps. Hackney / King's Cross DTC brands building loyalty + subscription companion apps to Shopify storefront.
• B2B field-ops apps. London real estate, construction, property management — offline-first apps with sync, photo capture, e-signature.
• Content and media apps. the City of London publishers building audio / video / subscription apps with playback, downloads, push.

Different category, different approach — so I don't ship templates. Every engagement starts with discovery against your actual London market context.

The mobile-app development engagement, step by step

I work via a transparent process that 130+ clients have completed end-to-end. Each phase has a fixed deliverable that you receive in your hands. No "wait a month while I design" — you know what's happening every week, with weekly Slack updates and one Zoom sync at 8am London / 3pm Kyiv.

1. Architecture and stack decision (week 1–2). RN+Expo vs fully native, state management, data layer, third-party SDK list, infra (EAS / Firebase / Supabase / AWS).
2. Setup and scaffolding (week 2–3). Repo structure, CI/CD (EAS Build / Bitrise / Fastlane), code-style and lint config, basic CI tests, environment variables.
3. Core build (week 3–14). Iterative sprint-based build: navigation, auth, key flows, native modules where needed, push / deep-link / OTA infrastructure.
4. Backend integration (week 6–14). API client (REST / GraphQL / tRPC), offline cache, retry / queue logic, error boundaries, optimistic UI.
5. QA and beta (week 14–18). Internal test (TestFlight + Firebase App Distribution), bug fixing, performance profiling (60-fps verification, memory leaks).
6. Store submission (week 18–20). App Store + Play Store assets prepared, app review responses drafted, phased release configured.
7. Post-launch ops (week 20+). Crash monitoring, OTA updates for fast fixes, feature flags for safe rollouts, ongoing performance review.

What you receive when the mobile-app development project completes

• Architecture document: stack decision, data model, integration map, infrastructure topology.
• Production codebase: React Native / Expo or native iOS+Android, TypeScript, full test coverage on business-critical paths.
• CI/CD pipeline: EAS Build / Bitrise / Fastlane, automated builds, signed releases, beta and production tracks.
• Native modules (Swift / Kotlin) for hardware-specific features, bridged and tested.
• Push / deep-link / OTA-update infrastructure (APNs / FCM, universal links, CodePush / EAS Update).
• Observability stack: Sentry / Bugsnag, structured logs, feature flags (LaunchDarkly / GrowthBook).
• Store-submission packages: assets, screenshots, descriptions, privacy nutrition labels, ITP / ATT compliance.
• Operations runbook: release procedure, rollback, on-call, common-issues playbook.

Why hire a Ukraine-based Senior instead of an London agency

London has a deep pool of talent — and rates that match. A typical Senior at a the City of London agency: $180–280/hour. A 12-week engagement at a respectable Shoreditch studio: $80,000–180,000. The work is excellent, but the cost makes it inaccessible for most early-stage startups, mid-sized DTC brands, and bootstrapped B2B SaaS companies.

The remote Ukraine-Senior model gives you:

• 30–60% cost reduction. Same Senior expertise, same deliverables, transparent fixed-fee USD pricing.
• Single point of contact. No account manager, no project coordinator, no creative director "stepping in" mid-call. You talk directly with the person doing the work.
• Async-friendly cadence. The 7-hour gap (London EST → Kyiv) is a feature: I work while you sleep, you wake up to demos and questions in Slack, we sync 1× per week on Zoom.
• Production-grade quality. Same modern stack (Next.js, React, TypeScript, Tailwind), same accessibility (WCAG 2.2 AA, ADA-compliant), same handoff specs as a top-tier London agency.
• Transparent fixed pricing. No hourly invoices, no scope-creep surprises. You know the total before we start.

USD pricing model

All projects are quoted as fixed fee in USD, paid 50% upfront / 50% on delivery (or split into milestones for projects > $20K). No hourly invoices. If scope changes mid-project — we re-quote, you approve in writing, and the change is added with a clear delta.

Indicative ranges to set expectations (every quote is bespoke, but these brackets are realistic):

• UI/UX design — landing or simple website (4-6 weeks). $8,000–18,000. London agency equivalent: $30,000–80,000.
• Corporate website — full design + dev (8-12 weeks). $20,000–45,000. London agency equivalent: $80,000–250,000.
• B2B SaaS / web app — design + frontend + backend (16-28 weeks). $50,000–180,000.
• UX audit (2-3 weeks). $4,000–9,000.
• Branding — full identity system (8-12 weeks). $12,000–30,000.
• SEO retainer (3-6 months minimum). $2,500–6,000/month.
• Fractional CPO / consulting (15-20 hrs/month, 6+ months). $4,000–8,000/month.

Discounts apply when you bundle services (e.g. design + development + SEO together) — typically 15-25% vs. ordering each separately.

How the async workflow handles the timezone gap

The 7-hour difference between London (EST/EDT) and Kyiv (EET/EEST) is the biggest concern most London clients raise — and it's the easiest to solve. The honest answer: most London startup founders and product teams already work async with Slack-first cadence. The remote-Ukraine engagement just formalises what's already happening internally.

• Daily Slack handoff. When you wake up at 8am London time, I've already worked 8 hours. There's a thread in #project with the day's progress, demo link (Figma / Vercel preview), and 2-3 specific questions that need your call. You answer over coffee — by 4pm London time I'm already incorporating your feedback.
• Weekly Zoom sync. One 60-90 minute call per week, scheduled at 8am London / 3pm Kyiv. We walk through what shipped, what's next, what's blocked.
• Loom for async demos. Instead of scheduling a meeting to "show you what I built", I record a 5-10 minute walkthrough.
• Notion / Linear for tracking. Whatever you use, I'll join. No new tool to learn.
• Emergency Zoom on demand. Critical decisions get a 15-minute Zoom call within 4 hours of request, regardless of timezone.

Cases — London and US clients in my portfolio

My portfolio contains 130+ projects, including B2B SaaS for US founders, DTC brand sites for London and LA-based companies, and fintech dashboards for clients on the East Coast. For NDA reasons I can't list every client publicly — but on the discovery call I'll walk you through 5-10 most-relevant cases for your specific niche.

Other services for London businesses

• UI/UX design
• Web development
• Mobile app design
• Mobile app development
• Branding and logo design
• E-commerce
• CRM / ERP / SaaS
• SEO, Google Ads, SMM, email marketing
• UX audit, CRO
• Business consulting, product strategy

Other US and EU cities I serve

• Los Angeles — entertainment, creative agencies, e-commerce
• San Francisco / Bay Area — B2B SaaS, deep-tech, AI
• Boston — biotech, ed-tech, university spinoffs
• Austin — startups, gaming, tech
• London — fintech, B2B SaaS, creative
• Manchester — northern tech hub, sport-tech, MediaCity
• Edinburgh — fintech, ed-tech, data science

Full list of locations on the "Service Areas" page.

Ready to discuss your London project?

Fill out the contact form or message me through the channels in the footer. The first 60-90 minute call is free — we'll discuss your business, product goals, indicative scope, USD budget range, and timeline. If you have an existing site / app, I'll do a quick express-review and show you 3-5 issues that can be fixed in the first week, even before signing a full engagement.

Common mistakes London businesses make commissioning mobile development

• Hiring on hourly rate. A $25/hour practitioner in Eastern Europe is statistically a junior at best. The 30-60% cost gap with London agencies isn't from hourly rate — it's from removing layered agency overhead.
• Skipping the discovery phase to "save money". A 1-2 week paid discovery is the cheapest insurance against a $50K mistake.
• Not asking about IP and ownership. Get this in writing before kickoff.
• Underestimating the value of single-contact engagement. Talking directly to the person building your product cuts requirement-translation losses by ~40%.
• Treating mobile development as a one-off project. The strongest results come from continuous iteration, not handoff-and-forget.

2025-2026 trends I apply on London client mobile development projects

• Swift 6 + Kotlin Multiplatform for shared business logic, native UI
• Live Activities + widgets as growth surfaces
• Apple Pay + Google Pay as default checkout in fintech apps
• Privacy-first analytics — App Tracking Transparency consent flows
• Offline-first with proper conflict resolution
• Push notifications optimised for D7 retention, not just opens
• Subscription apps with proper StoreKit 2 + Google Play Billing 6