Alex Batten, Freelance .NET & Full-Stack Engineer in Denmark

Last updated: July 29, 2026

Alex Batten is a software engineer based in Denmark with a BEng in Software Technology from the Technical University of Denmark (DTU). Most of my work is in .NET and full-stack web, with API and enterprise integrations and some AI/ML data work. I care about clean, functional code, solid architecture, and building things that actually work. Outside of coding I'm into strength training and music production, from audio engineering to composition.

I'm available for freelance and contract work: .NET and full-stack web apps, REST APIs and enterprise integrations, and AI/ML features. Remote across the EU on CET. Email alex.batten1234@gmail.com (alex.batten1234@gmail.com) or send a request through alexbatten.dk.

Experience

Senior Software Engineer, AI Infrastructure — Alignerr (Contract, 2026–Present)

Designing, building, and scaling the production infrastructure behind AI training, evaluation, and deployment pipelines used by millions. Working primarily in Python and TypeScript across backend services, APIs, and data pipelines, architecting for reliability and long-term maintainability at scale on cloud and containerized environments. Collaborating asynchronously with ML engineers, researchers, and product managers across a global distributed team, covering system design, code reviews, debugging across distributed systems, and contributing to engineering best practices.

Stack: Python, TypeScript, AI Infrastructure, Distributed Systems, Data Pipelines, Cloud, Containers.

Backend Developer — Acconta (2026–Present)

Designed and shipped production microservices on a multi-tenant SaaS platform (.NET Aspire, ASP.NET Core, EF Core), each taken from prototype to deployed service with OpenAPI/NSwag generated typed clients. Owned Stripe billing end to end: subscriptions and seat logic (proration, credits, plan switching, yearly plans, webhooks, secret hardening), plus a working subscription flow prototype in the Next.js client. Implemented Danish tax compliance: VAT reporting to SKAT via the NemVirksomhed service (SOAP with WS signing), computing all 17 VAT return fields, plus SAF-T import with schema validation. Also built standalone integrations for daily currency rates (National Bank) and company data via CVR (Danish Business Authority).

Stack: C#, .NET Aspire, ASP.NET Core, Entity Framework, Microservices, Stripe, Next.js.

AI Data Annotator — Outlier (2025–Present)

Contributed to advanced AI model development through data annotation, prompt engineering, trajectory refinement, and QA across projects including Clutch Zayu, Maraca Camera, Mechanic Astrologer, and Meter Pavilion (OpenClaw). Crafted system prompts defining model behavior and constraints, and designed single and multi-turn conversational and agentic datasets spanning 50+ risk categories including bias, misinformation, privacy, and safety. Built autonomous agent trajectories exercising skill discovery, memory, long-horizon context, and native tools (cron, sub-agent delegation), and refined Golden Trajectories for efficiency and grounding. Served as both author and reviewer on Mechanic Astrologer.

Skills: AI/ML, Prompt Engineering, Agentic AI, Data Annotation.

Software Development Intern — IT Operators / Simple Agency Group (2024)

Developed REST APIs with auth, rate limiting, and monitoring. Built fullstack web apps with Angular, .NET, and Bootstrap, including JWT auth, real-time dashboards, and automated reporting. Maintained and optimized ERP systems in production.

Projects

Professional work at IT Operators / Simple Agency Group

Accelo → Business Central Integration (Bachelor Project)

Fullstack application bridging two enterprise platforms, transferring and reviewing time registrations from Accelo (PSA) into Microsoft Business Central (ERP). Built a custom UI for reviewing and adjusting hours before syncing. Designed the data model in MSSQL, implemented multi-tenant authentication via Microsoft Entra ID, and containerized the entire stack with Docker in a Jenkins CI/CD pipeline. Fully tested, with unit tests on both layers plus integration tests using Selenium and WebApplicationFactory.

Uno X — Custom REST API (Client: ISTOBAL)

Custom API for ISTOBAL (car wash manufacturer) serving operational data to Uno X (Nordic fuel station chain), with a custom token-based authentication system and rate limiting with automated email alerts on threshold breach.

Eye4u — Automated SMS Alert System (Client: Eye4u)

Extended a surveillance customer portal with automated SMS notifications triggered by medicine-cooler temperature deviations detected across a sensor network, reducing the risk of unnoticed electrical or staff errors. Built as a multi-tenant SaaS module, each customer with their own sensor configuration and alert thresholds.

Internal Monitoring Dashboards (IT Operators)

Real-time dashboards deployed on Raspberry Pis for office TV screens, monitoring time registrations and cron job health to track work efficiency and catch failed jobs early.

TIMEVAT — External API Integrations (Client: TIMEVAT)

Integrated the EU VIES API for VAT number validation and the Danish National Bank API for daily currency exchange rates into a VAT compliance platform.

Personal projects

Invarix Guard — AI safety library for .NET

A plug-and-play AI safety library for .NET, shipped as a NuGet package (Invarix.Guard). Covers several AI safety categories out of the box, including prompt injection, PII, and content safety, so apps can add guardrails in a few lines of code. Website: invarix.dk. NuGet: nuget.org/packages/Invarix.Guard.

Invarix Guard Evidence — tamper-evident AI audit trail for .NET

A free .NET library (Invarix.Guard.Evidence), licensed under Elastic License 2.0, that records AI decisions as an append-only audit trail. Each decision is stored as a CloudEvents event keyed on SHA-256 hashes rather than the prompt text. Batches are sealed into an RFC 6962 Merkle tree and signed with the customer's own Ed25519 key, so an auditor can prove no record changed after sealing using standard Certificate Transparency tooling. Includes retention with legal holds, signed deletion certificates, and a streaming export endpoint. Runs fully in process with no outbound calls. Website: invarix.dk. NuGet: nuget.org/packages/Invarix.Guard.Evidence.

Hemi-Sync Guided Meditation App

A concept app for generating customizable guided meditations using AI-driven text-to-speech layered with Hemi-Sync binaural beat technology for brainwave entrainment. Built in React Native targeting both iOS and Android. Currently paused.

Distortion VST Plugin

An audio distortion plugin with bitcrushing built with the JUCE framework (C++), compatible with most DAWs as a VST. GitHub.

Skills & Tools

Languages: C#, C++, Python, Java, TypeScript, JavaScript, Kotlin, SQL.

Frameworks & Libraries: ASP.NET Core, Entity Framework, Angular, .NET, .NET Aspire, Next.js, React Native, Bootstrap, JUCE.

Concepts & Practices: REST APIs, System Design, Distributed Systems, Agile/Scrum, CI/CD, JWT Auth, Docker.

Other: Git, ERP Systems, Multi-tenant SaaS, Audio Engineering.

Education

BEng Software Technology — Technical University of Denmark (DTU), 2021–2025

Electives in Computer Graphics, Rendering, C++ Programming, and Engineering Economics. Bachelor's project: an integration between two ERP systems built from scratch. GPA: 7.62 (Danish 7-point scale).

Recommendations

Mike Valencia — CEO at Simple Agency Group

Recommended Alex Batten on LinkedIn for his work on development, software, and integrations. View the recommendation on LinkedIn.

Erik Seifert

Endorsed Alex Batten for C#, .NET Framework, and Entity Framework (EF) Core.

Contact

Email: alex.batten1234@gmail.com (alex.batten1234@gmail.com).
GitHub: github.com/AlexBatten.
LinkedIn: Alex Batten.