Mobile apps · AI automation · Revenue growth

Products that work — and make money

Apps, AI assistants, automation and analytics. I design, build and ship it myself — no team overhead, no account managers, no three-month approval cycles. Three of my own apps are live in the stores with real revenue.

Discuss your project → First call is free. I reply within a day.
14+ years
in engineering and IT
6+ years
in commercial development
3
apps of my own in the stores
Yevgeny Yezub
Mobile DeveloperAI · Automation

Sound familiar?

01

Your contractor shipped an app that lags and crashes — and now nobody can untangle it.

02

You have the idea and the budget, but hiring a five-person team is slow and expensive.

03

The product is live but doesn't earn: nobody buys the subscription, there's no analytics, nobody tests anything.

04

Your team and your support inbox are drowning in manual work a machine should be doing.

05

Everyone around you is "adopting AI" and you still have no answer for what it would actually do for your business.

I handle all five. Not as an outsourced pair of hands, but as a technical partner accountable for the outcome — not for ticket counts.

Two tracks

Tap a card to expand the details
A · Build it and fix it
01
Full app build
from $8,000 · 6–10 weeks

From idea to a published App Store / Google Play app. One person, the whole chain.

  • Architecture, UI, API integrations, caching and offline support
  • Subscriptions and in-app purchases (StoreKit / RevenueCat), paywalls
  • Analytics and crash reporting from day one (Firebase, Amplitude)
  • Widgets, Apple Watch, push notifications — where they make sense
  • CI/CD, store submission and handling Apple review
02
AI-accelerated prototype in 2 weeks
from $3,000 · 10–14 days

Test the idea before you commit real money. A working prototype you can show an investor or put in front of real users.

  • A product you can tap, not pictures in Figma
  • The core of the product built properly, secondary screens left out
  • You finish with a firm estimate for the full build
  • The prototype fee counts toward the project if we continue
03
Audit and rescue of an existing app
from $1,500 · 5–10 days

Your app is slow, crashes, drains battery, or nobody dares touch it. I take it apart and fix it.

  • Profiling in Xcode Instruments to find the real bottlenecks, not the obvious ones
  • SwiftUI render optimisation — on one production app this delivered a 10x+ improvement
  • Diagnosing data races and crashes in concurrent code
  • A written report: prioritised issues, each with an effort estimate

I've taken two production apps to a 100% crash-free rate — one of them serving up to 1.5 million daily active users.

B · Automate it and grow the revenue
04
AI assistants and chatbots
from $2,500 · 2–4 weeks

A bot that actually works, instead of replying "sorry, I didn't understand that".

  • Support assistant grounded in your own knowledge base: documents, policies, past conversations
  • Sales and lead qualification bot that hands qualified leads to your CRM
  • Telegram, WhatsApp, website widget, or an internal bot for your team
  • Clean handoff to a human on hard cases, with the context intact
  • Honest economics: we measure how many conversations it closes without people
05
AI features inside your product
from $3,500 · 3–5 weeks

Not a separate bot — intelligence inside the app itself.

  • Personalised recommendations driven by your users' own data
  • Content generation, summarisation, semantic search across your data
  • Document, image and voice processing
  • API cost control and a predictable cost per request

In Surfcast it works like this: normalised forecast data plus the user's profile go to the Claude API, and the structured response renders as native UI.

06
Process automation
from $1,500 · 1 week and up

Anything your people do by hand to the same script should be done by a machine.

  • Pipelines and integrations between your services: CRM, spreadsheets, email, messengers, payments
  • Automated data collection and parsing, scrapers, monitoring
  • Content generation and auto-publishing to Instagram, Telegram and Facebook — with human approval before anything goes out
  • Recurring reports that arrive where you actually read them
  • Built on minimal infrastructure: no unnecessary servers or subscriptions, and you own all of it
07
Analytics, conversion and ARR growth
from $2,000 for an audit · from $1,500 / month ongoing

You have a product and users but no money. This is where I find the leak.

  • Funnel audit: exactly where users drop off between install and payment
  • Proper product analytics set up (GA4, BigQuery, Firebase, Amplitude, RevenueCat)
  • Paywall and pricing: A/B tests on price, tier composition and copy
  • AI-generated hypotheses from your own data, queued and tested in order
  • ASO and store listing conversion, plus a monthly report

I run all of this on my own apps: subscription price A/B tests, Remote Config paywalls, RevenueCat Experiments, and a pipeline that proposes the next hypothesis on its own.

08
AI inside your team
from $2,000 per workshop · from $4,000 for a rollout

"Not buy everyone a subscription" — actually teaching a team to move faster.

  • Process audit: where AI pays off and where it just gets in the way
  • Rolling AI into engineering: Claude Code, review workflows, agents, MCP integrations
  • Guardrails and templates so quality doesn't drop as speed rises
  • A live workshop for the team plus support through the first month

I spent seven years training customer engineers around the world. Same job — different tools.

09
Fractional CTO
from $2,500 / month

For non-technical founders. I'm your engineering judgement, part-time.

  • Stack choices, realistic timelines and budgets, vetting contractors
  • Code and architecture review for your existing team
  • Which metrics matter and which hypotheses to test
  • Untangling App Store and Google Play rejections

Not sure what you need? Describe the problem in two sentences. I'll tell you honestly whether you need me at all, and what it would cost.

Discuss your project →

Not promises — shipped products

My own product · App Store

Surfcast — Waves, Wind & Tides

Surf forecasting: waves, wind, precipitation and tides. Designed, built and shipped solo — including the app icon and visual identity.

Swift / SwiftUIMVVMWidgetKitFirebaseAI recommendations
  • Disk cache, request coalescing and background refresh to cut redundant network calls
  • Home screen and lock screen widgets built with Swift Charts
  • AI spot recommendations: forecast data and user profile go to the model, the response renders as native UI
  • Firebase Analytics, Crashlytics, Performance, Remote Config and App Check
Shipped: May 2026 · Solo View on the App Store →
My own product · 6 years in production

BaliTideForecast (iOS)

Tide, swell and wind forecasting for surfers. In production since 2020 and generating revenue.

4.8★~1,000 MAU~237 DAUReal MRR
  • Grew it to a 4.8-star rating through iterative releases, A/B-tested subscription pricing and analytics-driven decisions
  • Hybrid SwiftUI/UIKit architecture with a cache-then-network strategy and graceful fallback to stale data
  • Subscriptions (StoreKit / RevenueCat) with Remote Config–driven paywalls
  • Widgets, an Apple Watch companion app, HealthKit, and a Firebase backend I built and own
My own product · Android

BaliTideForecast (Android)

I wrote the Android version from scratch, alone.

KotlinJetpack ComposeMaterial 3StateFlow
  • Custom hand-drawn tide chart on Compose Canvas with interactive time scrubbing
  • Coroutine-based HTTP client, multiple REST integrations, offline caching
  • Secure keystore and API-key handling, signed AAB release pipeline for Google Play
Automation · My own project

Content generation and auto-publishing pipeline

A system that writes the copy, generates the images and publishes to Instagram, Telegram and Facebook — with human approval before anything goes live.

  • Minimal infrastructure: no unnecessary servers, no third-party subscriptions
  • One-tap moderation directly in the messenger
  • Full ownership: all code and all keys stay with the owner
Automation · My own project

Revenue growth analytics loop

A pipeline that pulls product data, sends it to the model and returns ready-to-run A/B test hypotheses.

GA4 → BigQuery → AI → hypothesis queueRevenueCat ExperimentsRemote Config
Client work · Real-time

POKS — real-time poker

Mobile poker with real money transactions. Senior iOS Developer, 2.5 years.

900+ commits0% crash rateWebSocketgRPC
  • Layered networking architecture and a typed client with request idempotency
  • Diagnosed and fixed critical race conditions in concurrent multi-session real-time flows
  • Improved SwiftUI rendering performance by over 10x — zero downtime
Earlier on the same product — iOS Team Lead, a team of 5 engineers App Store →
Client work · High load

PlanetVPN

A VPN app with up to 1,500,000 daily active users. Senior iOS Developer.

  • Reduced the crash rate to 0% using Instruments, crash reports and third-party analytics
  • Researched and rebuilt the networking framework, then integrated it into the project
  • Refactored legacy code; integrated Appodeal and AppsFlyer
Client work · Social

DaGama

A location-based social app: interactive map of places, personalised feed, profiles, notifications.

UIKitMVVMApollo GraphQLGoogle Maps SDK
Yevgeny Yezub

18 years in engineering

I started as a field engineer in telecoms — seven years travelling the world training customer engineers. Then my own business, then project management at a digital agency for enterprise clients. Since 2019, development: from engineer to team lead running five people, and three apps of my own shipped to the stores along the way.

Field engineeringOwn businessManagementDevelopmentMy own products
More about me →

How I work

STEP 01

A 30-minute call, free

You describe the problem, I ask the awkward questions.

STEP 02

A firm quote

A number, a date, and exactly what's included. If it isn't a job for me, I'll say so and point you somewhere better.

STEP 03

Weekly builds

Every week you get something you can install and use. No "I'll show you at the end".

STEP 04

Handover

Code, documentation, credentials, keys, pipelines — all yours. No lock-in.

The questions I get most often

What does an app cost? +

From $8,000 for an MVP. The exact figure comes after our call — it depends on screen count, integrations and whether you need a backend. If you'd rather test the idea first, a two-week prototype starts at $3,000.

How long does it take? +

MVP: 6–10 weeks. Prototype: 10–14 days. Chatbot: 2–4 weeks. Audit of an existing app: from 5 days.

Do you work alone or with a team? +

Alone. That's precisely why it's faster and cheaper: no managers, no context lost between people, no time burned on internal alignment. For specialist work like heavy visual design I bring in contractors I've worked with before.

How is your bot different from a $20/month builder? +

A builder follows a script and breaks on the first question nobody anticipated. I build an assistant grounded in your knowledge base, with clean handoff to a human, real integration with your systems, and honest numbers on how many conversations it closes without people.

Do you guarantee revenue growth? +

No, and nobody honest does. What I guarantee is different: you'll see exactly where the money leaks, you'll have a queue of testable hypotheses, and you'll have the infrastructure to test them. After that it's a question of iterations.

Does my data stay with me? +

Everything runs in your environment, on your keys and your accounts. I don't hold your data. If the work is sensitive, we can talk about running local models.

Is it iOS only? +

iOS (Swift, SwiftUI) is my core specialism. I build Android with Kotlin and Jetpack Compose, and automation and bots in Python and Node.

Who owns the code? +

You do. Completely, from day one, including the repository and every credential.

How does remote work in practice? +

I've worked remotely with clients across time zones for eight years. I schedule calls around you and keep status in writing, so you never have to chase me to find out where things stand.

Can you take over a project another contractor abandoned? +

Yes, and it's a common request. I start with an audit and tell you honestly whether fixing it is cheaper than rewriting it.

Tell me the problem — I'll give you a price and a date

The first call is free. If it isn't a job for me, I'll tell you straight away and point you to someone better.