Jakub Szymion

Senior Android Engineer — 12+ years shipping consumer apps, payments and growth

Looking for a Senior/Staff Android or Python backend role. Remote, EU time zones preferred. Available from December 2026.

Summary

Senior Android engineer with 12+ years shipping consumer apps at scale, most recently on Dropbox's Mobile Growth (monetization) team. I own features end to end — technical design, implementation, rollout, measurement — and have repeatedly been the sole Android engineer on cross-functional growth and billing projects. Strong track record in subscriptions, payments, ad attribution and A/B experimentation, with a habit of finding long-standing defects nobody else had noticed. I also build Python/Django backends, both professionally and in my own projects, and work daily with AI coding tools (Claude Code, Codex) as a core part of my workflow.

Experience

Mar 2024 – Nov 2026remote

Dropbox Senior Software Engineer

Mobile Growth (monetization) team on the Dropbox Android app; previously Mobile Previews.

  • Designed and built the new-market testing program for Android as the sole Android engineer: an ad-attribution pipeline (Google Play Install Referrer, deeplinks) that identifies which campaign a user installed from and routes them to market-specific plans and upsell flows. Used to test pricing and plans in Indonesia and Colombia; owned technical design through rollout.
  • Built contextual upsells at key moments in the app (Play Billing IAP v2, base plan IDs, GrowthBook-driven variants), generating new subscription revenue while reducing churn.
  • Led an upsell-frequency calibration project: tuned prompt cadence through A/B experiments to maximise upsell revenue, delivering a significant lift in trial starts.
  • Drove mitigation of a major SEV — a long-standing billing defect that had allowed users to hold duplicate active subscriptions. Owned the investigation and shipped the client-side fix that eliminated most of the impact; a follow-up fix for the remaining edge cases was in rollout.
  • Found and drove the fix for a years-old bug in the traffic proxy that had been silently corrupting attribution data; identified the root cause and coordinated the repair across teams.
  • Hardened push-notification analytics: gave every notification a stable ID and corrected event reporting, turning engagement data into a reliable input for growth decisions.
  • Built the Android front end for the signature-request flow in the Dropbox app on top of an existing backend (Mobile Previews team).
Oct 2021 – Mar 2024remote

Sendwave Senior Software Engineer

Payments team on the Sendwave money-transfer app (fintech).

  • Rewrote the pay-in side of the app — the flow that accepts payments from users — improving reliability and maintainability.
  • Implemented multi-currency recipients, letting users send to recipients in different currencies.
Oct 2020 – Sep 2021London, remote

uMotif Senior Software Engineer

  • Delivered new functionality and improvements across uMotif's patient-facing clinical data-capture apps.
Jul 2019 – Oct 2020London, remote

Babylon Health Senior Software Engineer

Native Android app, team of ~40 Android engineers; architecture built on Orbit MVI.

  • Owned new functionality and improvements to the chatbot triage feature.
  • Implemented a generic asynchronous feature as the sole developer within a large, multi-squad codebase.
Dec 2017 – Jul 2019London, remote

Tigerspike Senior Software Engineer

  • Built multiple Android apps from scratch and extended existing ones for agency clients; largest project was Priority Pass.
  • Worked with distributed client teams across time zones, travelling on site when required.
Jun 2015 – Jul 2017Wrocław

RST-IT Senior Software Engineer (now Software Brothers)

  • Introduced MVVM with Data Binding to the company while it was still in beta; it became the company-wide standard.
  • Built backend services (Python) behind the company's mobile apps alongside Android work, plus DevOps duties — about a fifth of my time.
  • Worked across many client projects — greenfield, feature work and maintenance — gaining breadth across the Android API surface.
Mar 2014 – May 2015Wrocław

DOOK.pro Android Engineer

  • Added features to a language-learning platform; built a food-ordering app MVP from scratch.
Sep 2012 – Mar 2014Wrocław

LogToMobile Android Engineer

  • Built multiple apps from scratch, usually as the only developer, while still at university; one took 2nd place in a Samsung S Pen SDK hackathon.

Skills

Languages
Kotlin, Java, Python (Django), Dart (Flutter)
Android
Jetpack Compose, Coroutines & Flow, Hilt / Dagger, Jetpack (Navigation, Room, Architecture Components), MVVM / MVI (Orbit), Retrofit, Firebase, Google Play Billing (IAP v2, base plans), Install Referrer, deeplinks
Backend
Python, Django, Django REST Framework, Celery, Redis, PostgreSQL
Growth
A/B testing & feature flags (GrowthBook, Optimizely), ad attribution, analytics instrumentation, subscription & upsell flows, incident (SEV) response
Testing
JUnit, Espresso, unit & UI test suites
Tooling
AI-assisted development (Claude Code, Codex, in-house LLM tooling), Git, CI/CD; earlier: RxJava, Data Binding, Koin

Education

BSc Computer Science and Management — Wrocław University of Science and Technology2010 – 2013