Tomi
Jokinen
Mobile Developer
I build modern Android and iOS apps with a focus on clean architecture, great UX, and long-term maintainability.
Production Apps
Mobile applications available on global app stores, built with a focus on user experience and performance.
Navimo
Production mobile app for purchasing and managing travel eSIMs, providing connectivity in 200+ destinations worldwide.
Key Contributions
- Led Android app development from scratch using Kotlin and Jetpack Compose
- Participated in the full app development lifecycle across both Android and iOS
- Contributed to iOS development using Swift and SwiftUI in collaboration with the iOS team
- Built core flows for purchasing, installing, and managing travel eSIMs
TravelWifi
Production mobile app for managing data plans for portable hotspots and purchasing eSIMs, used by customers worldwide.
Key Contributions
- Led development of the Android app from scratch during a React Native → native migration
- Developed and maintained features across both Android and iOS, owning the full release and publishing pipeline
- Introduced Datadog RUM and reduced per-session error rate from ~5% to near zero
Core Stack
A snapshot of the technologies I use regularly in production work.
Experience
Senior Mobile Engineer
TravelWifi
- ◆Owned the end-to-end mobile development lifecycle for Android and iOS applications, from requirements gathering and technical design to implementation, release, monitoring, and ongoing maintenance.
- ◆Designed application architecture and UX flows, and architected a modular white-label Android app using Jetpack Compose to enable flexible client-specific customization.
- ◆Led the technical design and implementation of in-app eSIM provisioning on Android, integrating with the Android Telephony API and EuiccManager, including carrier app privilege management for specific eSIMs based on their ARF.
- ◆Designed and implemented comprehensive MiFi device management features, enabling eSIM download, installation, removal, switching, and profile management via WiFi and Bluetooth connections.
- ◆Collaborated closely with product, design, and backend teams throughout discovery, development, and delivery phases to ensure scalable, secure, and maintainable solutions.
- ◆Established and followed modern development workflows, including code reviews, CI pipelines, version control, and release processes to ensure high-quality and reliable deployments.
- ◆Owned production releases and post-release operations, including publishing to Google Play and the App Store, monitoring crashes and performance, and delivering regular updates and improvements.
Relevant Skills: React Native, Kotlin, Jetpack Compose, Material Design, Hilt, Dagger, Retrofit, Swift, SwiftUI, Firebase, Crashlytics, DataDog, Android Telephony / EuiccManager, Human Interface Guidelines, App Store, Google Play
Frontend & Mobile Engineer
Freelance
- ◆Developed web and mobile applications for startups and small businesses using React and React Native across iOS and Android platforms.
- ◆Designed UI-rich, responsive interfaces and implemented client-facing features by translating business requirements into technical solutions.
Relevant Skills: React, React Native, JavaScript, TypeScript, REST APIs, Firebase, Git
AI Data Analyst
Telus International AI Data Solutions
- ◆Collaborated on AI training projects, evaluated model performance, including those related to speech recognition, voice assistants, search algorithms, and Large Language Models (LLMs).
- ◆Applied quality assurance methodologies to improve AI model training efficiency and dataset quality.
- ◆Ensured continuous improvement of AI datasets through rigorous evaluation and feedback loops.
Education
M.Sc. in Computing Sciences(coursework completed)
Tampere University
- ◆Database establishing, modeling, design, SQL queries.
- ◆Data Structures and Algorithms.
- ◆Programming: C, Java, JavaScript, Python.
- ◆Full Stack Web Development.
- ◆Software Production.
- ◆Artificial Intelligence, Machine Learning.
- ◆Cybersecurity.
Bachelor of Business Administration
Seinäjoki University of Applied Sciences
- ◆International Business
Certifications & Courses
Create Serverless Applications
Microsoft / Coursera
This course is a part of Microsoft Azure Developer Associate (AZ-204) Professional Certificate. Azure Function development, deployment and testing. Evaluating Azure services for integration and process automation scenarios.
Kotlin Core
Hyperskill / JetBrains Academy
Kotlin syntax, application design with functional decomposition, key programming concepts, OOP decomposition, Java and Kotlin libraries
React (Basic) Certification
HackerRank
React (Basic) covers topics like Basic Routing, Rendering Elements, State Management (Internal Component State), Handling Events, ES6 and JavaScript and Form Validation.
CSS Certification
HackerRank
Cascading and Inheritance, text styling fundamentals, layouts, boxing of elements.
Machine Learning with Python
Aalto University
Introduction to machine learning concepts and implementation using Python.
Full Stack Web Development
University of Helsinki
Comprehensive course covering MongoDB, Express, React, and Node.js.
Advanced Programming
University of Helsinki
Advanced concepts in Java programming and software development.
Languages
Finnish
Native
English
Fluent
Spanish
Fluent
Get in Touch
I'm always open to discussing new projects, ideas or opportunities to work together.