Jarle Mathiesen
Senior software engineer · Oslo, Norway
Summary
I’m a senior software engineer in Oslo. I do my best work in product teams, close to the users and the problem, taking ideas all the way to something people rely on every day.
For eight years I’ve built systems where the numbers have to be right: pension premium calculation for Norway’s largest public pension provider, and reporting and invoicing at Posten Bring.
I use AI to raise both the quality and the scope of what I build, and I’ve shipped products with AI at the core: SummYT, a video summarizer with more than 200,000 registered users, and an assistant that analyses Posten Bring customers’ reports and invoices.
Experience
Senior consultant, Knowit
Client: Posten Bring
Analytics team. The department owns Mybring, Posten Bring’s self-service platform for business customers; the team works on its reporting and invoicing, replacing a legacy monolith and turning reports into analytics customers can act on.
- Led development of the new core reporting system that takes over from the legacy monolith.
- Maintained and extended a streaming API for customer emissions reports, calculated per shipment and built for the data volumes of Posten Bring’s largest customers.
- Built an assistant for reports and invoices on Spring AI and OpenAI models, with domain-specific tools that run aggregations and analysis on customers’ actual data.
- Held internal workshops and hackathons on generative AI and AI-assisted development, sharing what I learn as the field moves.
Founder, SummYT
My own product: AI summaries of YouTube videos, as a web app and a browser extension. Launched in 2023 as YouTube Summarized.
- Grew it to more than 200,000 registered users.
- Built it alone, full stack, including the browser extension.
- Own the whole product: engineering, operations and search engine optimisation.
IT consultant, Bouvet
Client: Statens pensjonskasse
Pension premium calculation for Norway’s largest public occupational pension provider (pension rights worth over NOK 500 billion). First on the legacy system, then on Prosjekt Presis: a new system delivered on time and on budget in 2022 that brought premium calculation in-house from an external vendor.
- Built Spring Boot microservices in Java and Kotlin, and parallel batch jobs for the most domain-heavy calculations.
- Helped build the data system SPK uses to forecast future pension costs, an input to the state budget.
- Set up continuous integration early in Presis, so the team could release often without regressions.
- Built a React and TypeScript visualisation app, using headless UI patterns for complex data tables.
- Became one of the most experienced developers on the team, created its onboarding process and trained new developers.
Software developer, RISE Research Institutes of Sweden
Linköping, Sweden
Software development at Sweden’s national research institute, alongside my MSc studies.
Projects
- Matstack
react-adonisjs: full-stack React Router apps on AdonisJS 6, with ORM, auth and dependency injection built in. 55+ GitHub stars.
Talks
- Your Service Layer Is a Mess (Here’s a Simple Fix)
Service layer patterns for backend applications. The fix ships as installable agent skills alongside the slides.
Skills
- Backend
- Kotlin, Java, Spring Boot, TypeScript, Node.js, AdonisJS
- Frontend
- React, React Router, Svelte
- Data
- PostgreSQL, SQL Server, High-volume batch and streaming
- AI
- LLM features and tool calling, Spring AI, OpenAI API, Coding agents (Claude, Codex)
- Platform
- Azure, Google Cloud, Docker, CI/CD
- Practice
- Product teams, Domain-driven design, Test-driven development
Education
- MSc, Computer Engineering, Linköping University
- One-year programme in Psychology, University of Oslo
- Google Cloud Professional Cloud Developer
- Microsoft Azure Fundamentals (AZ-900)
- Norwegian (native)English (fluent)Swedish (fluent)