Christian Funder Sommerlund

At Umbraco, I worked on the Umbraco Heartcore SaaS CMS product with a small team of other software engineers. My main focus was on improving reliability, performance, uptime, cost and code quality of the overall system.

Notable achivements:

• Design, implementation and integration of an automated end-to-end testing system.
• Research and implementation of infrastructure cost savings of ~400.000 DKK yearly.
• Migration of PostgreSQL databases across multiple major versions.
• Debugging and fixing database connection leaks and performance issues in various subsystems.
• Integration of instrumentation and error monitoring into various subsystems.
• Visualization of performance characteristics on dashboards.
• Maintenance of infrastructure as code, build pipelines, frameworks, code dependencies, ...

Backend technologies used:

• C#
• .NET Framework + 5 + 6 + 7
• ASP.NET
• PostgreSQL
• GraphQL
• ImageProcessor

Cloud services used:

• Azure App Service
• Azure Functions
• Azure Database for PostgreSQL
• Azure Service Bus
• Azure Blob Storage
• Azure Monitor Application Insights
• Azure Monitor Workbooks
• Cloudflare CDN
• Cloudflare Workers KV

Tools used:

• JetBrains Rider
• Git
• GitHub
• Slack
• Azure Repos
• Azure Boards
• Azure Pipelines
• Azure Portal
• Playwright
• Terraform
• Insomnia
• pgAdmin
• pg_dump/pg_restore
• Grafana

At Esoft, i mainly worked as Tech Lead for an unannounced upcoming product for photographers in the real estate sector. The product is a core business system with a dedicated backend and mobile apps on top. I also worked on stabilizing and modernizing existing legacy business applications.

Backend technologies used:

• C#
• ASP.NET Core
• Entity Framework Core
• GraphQL
• SQLite
• MySQL
• PostgreSQL

Tools used:

• Git
• Bitbucket
• Jira
• JetBrains Rider
• Docker
• Jenkins
• Sentry
• Insomnia
• Microsoft Teams

I worked as Tech Lead for the mobile ticketing platform used by about half of the public bus and train companies in Denmark. My main responsibilities included technical planning, system architecture, codebase quality assurance, developer mentoring as well as general software engineering.

Notable achivements:

• Ownership of ~100.000 lines business critical backend codebase, mostly built from scratch.
• Yearly handling of ticket purchases worth ~250 million DKK.
• Processing of ~1 million API requests daily, with average response time of < 50 ms.
• Technical integration with multiple payment providers (MobilePay, DIBS, NetAxept, ...).
• API design and auto-generated documentation for mobile apps, webshops, admin panels, ...
• Design of software patterns for thread safety, retrying and backoff, deferred execution, ...
• Live monitoring and metrics of system performance, error rates, latency, transaction failures, ...
• Implementation of database migrations for millions of rows of data.
• Mentoring of 10+ software engineers.

Backend technologies used:

• C#
• ASP.NET Web API
• Entity Framework
• Windows Server
• Microsoft SQL Server
• Microsoft IIS

Frontend technologies used:

• HTML
• CSS
• JavaScript
• Knockout

Tools used:

• Git
• Bitbucket
• Trello
• Visual Studio
• JetBrains ReSharper
• SQL Server Management Studio
• Raygun
• Grafana
• Insomnia
• Firebase

During the last semester of my master's studies, I worked as a teaching assistant for the introductory programming course at the department. I taught the fundamentals of modern object-oriented programming in Java for first-year students.

Students at Faculty of Science at the university are assigned to study groups with designated advisors during their first semester. As an advisor, I taught computer science students cooperative learning every fall semester during the last four years of my studies.

At Knowledge Lab I provided on-demand IT assistance for the small research center, as a study job. Most of my work involved deploying and maintaining CMS systems (Drupal mostly) for various research projects, tech support and various conference work.

As a personal teaching assistant, I worked as a long-time mentor for multiple younger computer science students with various learning disabilities. Through one-to-one sessions, I supported their learning with their individual challenges in mind. My work was financed by the State Educational Grant and Loan Scheme (SU).