Alex Batten, Freelance .NET & Full-Stack Engineer in Denmark
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.
Available for freelance and contract work. Email
alex.batten1234@gmail.com
(alex.batten1234@gmail.com), or see the
full CV, which also answers
frequently asked questions about availability, stack,
and how to start a project.
Experience
Senior Software Engineer, AI Infrastructure — Alignerr (Contract, signed 2026, not yet started)
Signed contract, first assignment still pending. The agreed scope is
designing, building, and scaling the production infrastructure behind AI
training, evaluation, and deployment pipelines: Python and TypeScript across
backend services, APIs, and data pipelines, architected for reliability and
long-term maintainability at scale on cloud and containerized environments.
The role also covers system design, code reviews, and debugging across
distributed systems, working asynchronously with ML engineers, researchers,
and product managers on a global distributed team. 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.
Generalist Expert, AI Evaluation — Mercor (Contract, 2026–Present)
Evaluating AI model outputs against structured evaluation guidelines and
writing the rationale behind every judgment. The work is close reading:
checking a response for factual accuracy, sound reasoning, instruction
following, and tone, then stating precisely where it holds up and where it
breaks down, with evidence. Applying the same standard consistently across a
wide range of subject areas so that assessments stay comparable between
reviewers. Skills: AI Evaluation, LLM Outputs, Structured Feedback, Technical
Writing.
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
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). Custom review UI, MSSQL data model, multi-tenant authentication via
Microsoft Entra ID, containerized with Docker in a Jenkins CI/CD pipeline,
with unit and Selenium integration tests.
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 token-based authentication and rate
limiting with automated email alerts.
Eye4u — Automated SMS Alert System
Extended a surveillance customer portal with automated SMS notifications
triggered by medicine-cooler temperature deviations across a sensor network.
Built as a multi-tenant SaaS module.
Internal Monitoring Dashboards (IT Operators)
Real-time dashboards deployed on Raspberry Pis for office TV screens,
monitoring time registrations and cron job health.
TIMEVAT — External API Integrations
Integrated the EU VIES API for VAT number validation and the Danish
National Bank API for currency exchange rates into a VAT compliance platform.
Invarix Guard — AI safety library for .NET
A plug-and-play AI safety library for .NET, shipped as a NuGet package
(Invarix.Guard). Covers 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.
Invarix Gate — action firewall for AI agents in .NET
A deterministic action firewall for AI agents, shipped as a NuGet package
(Invarix.Gate). It sits in front of an agent's tool calls and evaluates each one
against a policy before it runs, returning allow, warn, escalate, deny, or
terminate. Ten detectors cover destructive SQL, shell commands, git history
rewrites, cloud teardown, credential egress, and runaway loops, each grounded in a
dated public incident. Matching is pure CPU pattern work with no model call, so a
verdict lands in a median of 57 µs and is deterministic under a given policy.
Policy is authored in YAML or fluent C#, attaches through Microsoft.Extensions.AI
and Microsoft Agent Framework, and reports the surfaces it cannot see rather than
rendering a clean run. Ships with a 194 scenario policy corpus where roughly half
the cases assert a detector stays quiet.
Website: invarix.dk.
NuGet: nuget.org/packages/Invarix.Gate.
Hemi-Sync Guided Meditation App
A concept app for generating customizable guided meditations using
AI-driven text-to-speech layered with Hemi-Sync binaural beats, built in
React Native for iOS and Android.
Distortion VST Plugin
An audio distortion plugin with bitcrushing built with the JUCE framework
(C++), compatible with most DAWs as a VST.
Lab — writing and notes
Findings, unfinished ideas, and things worth someone else picking up, on
.NET, AI agent safety, and enterprise integrations. Read them at
alexbatten.dk/lab.
Skills & Tools
Languages: C#, C++, 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, Claude Code, ERP Systems, Multi-tenant SaaS, SAF-T,
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.
Freelance & Project Requests
Available for freelance and contract work: .NET and full-stack web
apps, REST APIs and enterprise integrations, and AI/ML features. Have a
project in mind? Send a request through the site or email
alex.batten1234@gmail.com.
