Peter Törnhult
> Profile
https://se.linkedin.com/in/petertornhult
> Knowledge & Sharing
> Companies

> Uptime
> Lang
Swedish, English
> Location
Stockholm, Sweden | Prague, Czech Republic
> _
Portfolio
> Expertise
“I help teams modernize and scale their mobile apps by improving architecture, performance, code quality, and development workflows — while coaching teams and lifting their technical capability.”
> Where I Deliver the Most Impact
- Android Tech Lead
- Senior Mobile Platform Engineer
- Mobile Architecture & Modernization Consultant
- Mobile Performance & Quality Engineer
- Senior Android Specialist
> Projects
SJ
At SJ, I played a key technical role in a major multi-year app and backend migration. I took lead responsibility on the technical side by driving decisions, safeguarding app quality, and supporting the team’s daily work. I successfully managed this under a tight 2-year deadline with constantly shifting variables, dependencies, and cross-team coordination. I improved the Android app and the microservices, mentored developers, introduced Kotlin to multiple teams, and strengthened architecture and security across the organization.
Bookbeat
At Bookbeat, I improved the overall app experience by optimizing the UI, implementing new features, and modernizing the codebase. I migrated legacy Java/Rx code to Kotlin with Coroutines, helped modularize the app, and pushed clean architecture practices throughout the Android team to create a more maintainable and scalable product.
UR
At UR, I modernized the entire Android app by converting it fully to Kotlin, introducing a unified coding style, and improving pipelines and test stability. I modularized the codebase, rebuilt the audio/video player with clean and testable architecture, delivered multiple new features, and supported other developers through mentoring and knowledge sharing.
> Blogs
7 Pro tips for working with Android XML Layouts
Practical tips to keep Android XML layouts clean, maintainable and performant — avoid hard-coded values, flatten view hierarchies, use appropriate ViewGroups, resource-prefixing, formatting and previews.
Hacking the Compose Bottom sheet
How to work around challenges using ModalBottomSheetLayout with tab navigation in Jetpack Compose — a practical solution to a tricky UI case.
Improving the Compose DropdownMenu
Techniques for making dropdown menus in Jetpack Compose more robust, predictable, and user-friendly when migrating from older UI paradigms.
Animated Selector in Jetpack Compose
How to recreate AnimatedStateListDrawable-style behavior in Compose for animated selectors during migration from XML UIs.
Testing Custom Views with Robolectric 4
A walkthrough for testing Android custom Views without a real device using Robolectric 4 — reliable and fast component-level tests.
Lifecycle & Fragments backstack
Explaining ViewModel & LiveData behavior with fragment backstack navigation and presenting a clean workaround for restoring views safely.
Kotlin Inline Classes in an Android World
An explanation of Kotlin inline/value classes, when to use them, and how they fit into Android architecture and performance constraints.
LiveData transformations
Understanding map, switchMap, distinctUntilChanged, and MediatorLiveData for clean reactive stream transformations inside ViewModels.
How to unit test Room: runInTransaction
A practical guide for properly testing Room database operations using runInTransaction for safe execution and predictable test behavior.
Beware of Kotlin Runtime bugs (Converting Java to Kotlin)
An overview of subtle runtime pitfalls when converting Java code to Kotlin — invaluable for teams migrating legacy Android apps.
Technology
> Mobile Development
- Android Development 10+ yrs / 12+ apps
- Kotlin Expert 8+ yrs / org-wide adoption
- Jetpack Compose multiple apps
- Modern App Architecture MVVM, MVI, MVP
- UI/UX Design Collaboration multiple apps
- Performance Optimization 20+ yrs / large-scale apps
- Security & Quality Assurance 15+ yrs
- Test-Driven Development (TDD)
- React Native
- PhoneGap, Cordova
> Web & Fullstack
- Frontend Development
- React.js5+ yrs / Klarna, ASSA ABLOY
- Node.js8+ yrs / Klarna, ASSA ABLOY
- JS (Vanilla)20+ yrs / vanilla
- Vue.js
- Ember.js
- Fullstack
- Responsive UI Design
- Code Quality & Maintainability 15+ yrs
- Servers
- Node.js
- Apache
- Tomcat (Standalone, JBoss)
- Nginx
- Jetty and more...
> Architecture & Backend
- Backend Architecture & Development 12+ yrs
- Node.js
- Dropwizard
- Spring Boot
- JBoss, Tomcat servlets and more...
- Microservices & API Design 6+ yrs
- Database Design & Management 10+ yrs
- MySQL, MariaDB
- Postgres
- SQL Server
- Firebase Realtime Database, Parse
- Room, SQLite, H2 and more...
- Secure & Scalable Systems 8+ yrs
> Cloud & DevOps
- Cloud Infrastructure 7+ yrs
- AWS
- Azure
- Google Cloud
- DevOps & Automation 8+ yrs
- Continuous Integration & Delivery (CI/CD) 10+ yrs
- GitHub Workflows
- DevOps Pipelines
- Jenkins
- CircleCI
- Hudson and more...
> Leadership & Process
- Team Leadership & Mentorship 10+ yrs
- Agile & Scrum Practices 10+ yrs / Certified Scrum Master
- Agile Collaboration 10+ yrs
> Programming Languages
- Kotlin ❤️ 8+ yrs
- Java 20+ yrs
- JavaScript 15+ yrs
- TypeScript 7+ yrs
- Python, PHP, C#, C / C++, Ruby, Groovy, HTML & CSS...
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