bastian lahr / freelance software architect
available Q3/26
DE EN
00 / Positioning since 2007 · Rodenberg, DE
.NET · Azure · AI-assisted delivery

Legacy .NET systems,
modernised without downtime.

Freelance software architect · Legacy modernisation with .NET, Azure & AI

I modernise existing .NET systems, bring them to the cloud where it pays, and accelerate delivery through AI-assisted engineering — pragmatic, no downtime.

Discuss a project → See services
Stack
.NET 10
Cloud
Azure
Engagement
Remote / DACH
Response
< 24h

Services

01 / Services four areas, one outcome: software that ships
01
/modernization

.NET modernisation

Lift existing .NET-Framework codebases to .NET 10. Strangler-fig over big-bang, production-stable at every step.

  • Migration .NET Framework → .NET 10
  • Monolith → modulith → microservices
  • Test harness & CI for brownfield
  • Performance & memory profiling
02
/cloud

Cloud transformation (Azure)

Lift-and-shift rarely works. I move workloads to Azure structurally — Container Apps, AKS, Functions — with IaC and cost awareness.

  • Azure Container Apps · AKS · Functions
  • Terraform · GitHub Actions · Azure DevOps
  • Observability (App Insights, OpenTelemetry)
  • Container & AKS tuning · cost guardrails
03
/backend

API & backend engineering

REST, gRPC, event-driven. Clean domain models, clear contracts, test coverage where it earns its keep — not everywhere.

  • ASP.NET Core · Minimal APIs · gRPC
  • EF Core · Dapper · PostgreSQL · SQL Server
  • Event-driven · Service Bus
  • DDD / Vertical Slices, in measured doses
04
/ai-delivery

AI / agent-assisted delivery

LLM workflows embedded in engineering — code migration, test generation, spec discovery. Measured, not magical.

  • Coding agents in CI/CD pipelines
  • LLM-driven code migration & refactoring
  • Test & doc generation from existing code
  • Evals & guardrails for production use
02 / AI delivery no hype · measurable throughput

Agents as a tool,
not as marketing.

The productive wins from LLMs and coding agents live in unglamorous places — migration scripts, test coverage, reconstructing API contracts from legacy code. I wire that into the pipeline, with evals and clear stop conditions.

  • Migration with agents: boilerplate automated, the rest goes through structured review.
  • Test generation from legacy code: characterization tests before refactoring.
  • Eval-first: an agent ships only when it passes a held-out eval set.

By the numbers

03 / By the numbers tracked, not estimated
17+
years of .NET
since 2007
6
stations
junior → senior → lead → freelancer
2007
first release
embedded · wpf
100%
remote, DACH timezone
german · english

Stack

04 / Stack tools I actually ship with

.NET

  • .NET 10
  • ASP.NET Core
  • Blazor
  • WPF · WinForms
  • EF Core · Dapper
  • xUnit · NSubstitute

Cloud

  • Azure (AKS, ACA, Functions)
  • Service Bus · Event Grid
  • Cosmos DB · SQL Azure
  • Terraform
  • GitHub Actions · Azure DevOps
  • App Insights · OpenTelemetry

AI / Agents

  • Claude · GPT-5
  • Local LLMs (Ollama, llama.cpp)
  • Coding Agents (Claude Code, Cursor)
  • Semantic Kernel · RAG
  • Evals · Guardrails
  • MCP integrations

Method

  • Domain-Driven Design
  • Trunk-Based Development
  • Strangler-fig migration
  • Continuous Delivery
  • Pair / mob programming
  • Architecture Decision Records

Cases (anonymised)

05 / Cases (anonymised) context · approach · result
case_01
E-government · federal agency

Microservice platform for a federal domain process

Built a microservice architecture in .NET Core for a domain process at a German federal authority. CI/CD on Azure DevOps set up from scratch, Azure services integrated into the service landscape — in production inside the agency.

since 2023 ongoing engagement
.NET Core .NET Core · Azure microservices
CI/CD CI/CD pipelines from scratch
case_02
3D · cloud platform

Cloud platform for 3D model processing

Redesigned a microservice architecture in ASP.NET Core for processing and serving 3D models. Internal and public UIs in Blazor, reusable CI/CD pipelines on Azure DevOps. Later as Co-Head of Development & Team Lead Microservices, owning the technical direction of the platform.

4 yr 4-year engagement (2020–2024)
Co-Lead Co-Lead Development & Microservices
Blazor Blazor · internal & public UIs
case_03
Industry · ERP

WPF ERP & mobile for mid-market manufacturing

Designed and implemented an ERP system in WPF for mid-sized production companies, paired with a Windows Mobile application for mobile order processing — right at the production line.

5 yr 5-year engagement (2009–2014)
WPF WPF · Windows Mobile
ERP ERP shipped end-to-end

About

06 / About bastian lahr
Bastian Lahr

Senior software architect with 17+ years in the .NET world — from WPF desktop to distributed cloud systems. I work as an independent for mid-market companies, software vendors and enterprise teams.

My focus sits where existing code and new requirements collide: modernisation over greenfield romance, cloud architecture with a budget, AI-assisted delivery without the hype folklore.

I deliver code, not workshops. If a whiteboard makes more sense, I'll say so up front.

📍 Rodenberg, DE 🌐 DE / EN ⏱ Q3 / 2026
07 / Contact → contact@lahr.dev

Concrete plan?
Drop me a line.

A short email with context and timeframe is enough. I reply within 24 hours on weekdays — usually the same day.

emailcontact@lahr.dev
phone+49 176 24316920
locationRodenberg, DE
timezoneCET / CEST
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