Backend & APIs
Designing, extending, and troubleshooting .NET services, REST and GraphQL APIs, integrations, and WebSockets.
.NET · ASP.NET Core · EF CoreSTATUS / Available for selected freelance engagements
Thomas Holm JespersenSenior Backend & Cloud Engineer
I make complex backend systems reliable, fast, and ready to scale.
I help teams tackle clearly scoped challenges across .NET, AWS, PostgreSQL, APIs, and distributed systems — from stubborn production issues to architecture and high-volume data.
12+years in software
Tech Leadstill hands-on
5–20 hrs/weektypical availability
Expertise
When your backend needs more than another pair of hands.
I do my best work on well-defined technical problems where experience with production systems, data, and system boundaries makes a real difference.
Cloud & distributed systems
Architecture and operations for event-driven workloads, services, and data pipelines on AWS — built for reliability, observability, and easier troubleshooting.
AWS · ECS · Docker · IoTData & performance
Diagnosing slow queries, data models, and ingestion pipelines when growing volumes or response times start to hurt.
PostgreSQL · TimescaleDB · SQLTroubleshooting & stabilization
Systematic troubleshooting across code, logs, infrastructure, and third-party integrations when the root cause is not obvious.
Production issues · Performance · IntegrationsSelected work
Real-world systems with real-world complexity.
Saveeye
IoT platform for real-time energy data
Hands-on responsibility for evolving the backend and cloud architecture, with a focus on scalability, performance, and reliable operations. The work also spans APIs, an app SDK, and a management platform for partners.
Scope: Architecture, implementation, data ingestion, partner integrations, and technical operations.Podster
Automated, AI-powered podcast localization
Backend and cloud workflows that brought transcription, translation, AI voices, sound profiles, and automated mixing together in one production pipeline.
Result: An automated production process for bringing podcasts to new languages and markets.Elva
From fragile plugin to a stable custom platform
A robust backend and admin solution that removed the dependency on an unstable WordPress plugin and gave the product a stable foundation for further development.
Result: Reliable day-to-day operations, controlled content management, and no business-critical plugin dependency.Experience
More than 12 years of technical ownership — from product development to cloud architecture.
Titles have never been the focus of my career. Ownership has been the common thread: since 2014, I have led projects, built business-critical platforms, and taken products from early ideas and architecture through to production and operations.
Duka
Taking ownership from day one
Led multiple projects across apps, web, SSO, and backend — including a billing platform serving more than 20,000 customers.
Fairytell · Podimo · Podster
Products, platforms & deeper expertise
Built .NET backends, native apps, and SDK integrations before moving deeper into cloud workflows, GraphQL, and automation.
Syntastic · Saveeye
Backend & cloud leadership
Co-founded Syntastic and served as Lead Backend Developer, owning backend and cloud delivery. I later joined our client Saveeye directly, where I am now responsible for backend architecture, integrations, and the reliable operation of its IoT platform.
Technical focus
CoreC# · .NET · ASP.NET Core · EF Core
CloudAWS · Azure · Docker · ECS · IoT
DataPostgreSQL · TimescaleDB · SQL · DynamoDB
APIsREST · GraphQL · WebSockets
ArchitectureDistributed systems · High-volume ingestion · Performance
Working together
A flexible way to add senior engineering capacity.
The strongest fit is a clearly scoped task, ownership of a technical workstream, or ongoing specialist support delivered remotely and mostly asynchronously.
- ✓Typically 5–20 hours a week
- ✓Remote, with async collaboration by default
- ✓Works alongside your existing team
- ✓Clear delivery, documentation, and handover
Contact
Let's find out whether I am the right fit.
Send me a few lines about the system, the problem, and the expected scope. I will give you a straightforward assessment of whether I can help.