/\_/\
                ( o.o )
                 > ^ <    "In code we trust, in bugs we debug."
              /|      |\
             (_|      |_)

Senior Software Engineer @ Yubico | Open Source Maintainer | Certified Scrum Master Building secure systems, AI workflows, and the occasional decentralized dream

📍 Stockholm, Sweden | 🗣️ English, Swedish (native) | Spanish, Portuguese (elementary)

Full-stack dev (mostly backend) with 11 years building microservices, APIs, and fixing thread safety bugs. BSc in Computer Science from Stockholm University.

I like writing clean C#, test-driven development, and reducing technical debt. Currently working at the intersection of security, AI, and blockchain—turns out one rabbit hole wasn't enough.

Mission-driven projects that improve society + code that doesn't crash in production + learning new tech = what gets me up in the morning.

Working on the Yubico.NET.SDK, a cross-platform SDK for YubiKey authentication targeting enterprise customers. Cryptographic signing, PKI, hardware security for .NET devs.

Day-to-day work:

• Authored 120+ PRs, reviewed 75+ PRs from contributors
• Mentoring on crypto correctness, backward compatibility, test quality
• Publishing signed libraries for Windows, macOS, Linux, Android
• Implementing FIDO2/CTAP protocols in C# and C
• Filed and resolved 25+ issues (bug fixes, features, build stuff)
• Performance improvements, logging, reducing tech debt

Some notable work:

Fixed production crashes on macOS when people plugged in/removed YubiKeys. Turns out callbacks were firing on garbage-collected delegates. Implemented thread-safe disposal patterns across all platforms.

31 commits, 4,000+ tests, kept code coverage at 50%. Poll-based event detection on Linux, CFRunLoop timeouts on macOS, deterministic finalizer testing, resource leak detection via file descriptor monitoring.

Implemented Client to Authenticator Protocol 2.2 with extension support, encrypted identifiers, FIDO2 capabilities for YubiKey firmware 5.4.3-5.8.3. Kept backward compatibility.

67 files modified, 40 commits, 3,964+ tests across Windows/Ubuntu/macOS. HKDF key derivation (RFC 5869), CBOR encoding, PIN/UV auth protocols, hmac-secret-mc extension.

Sweden's public radio (think NPR meets Spotify's engineering culture). Started as a dev, became team lead/scrum master for a while, then senior dev. Managed editorial tools and infrastructure.

Senior developer (2022-2024):

• Built microservices pipeline from .NET 5 → .NET 8
• Deployed to Kubernetes (Rancher) via ArgoCD + Harbor
• Created health monitoring dashboard (Vue 3 + .NET)
• Modularized GitHub Actions for build processes
• Stack: Aurelia, TypeScript, Vue 3, .NET 8, Azure Service Bus, RabbitMQ, SQL Server, Elasticsearch, Kubernetes

Scrum master/team lead (2017-2022):

• Led team managing 30 legacy applications with different tech stacks
• Implemented CI/CD for all systems (TeamCity → Octopus Deploy → GitHub Actions)
• Set up monitoring, logging, health checks everywhere
• Ran agile ceremonies while shipping code
• Transformed legacy chaos into manageable systems

Full-stack developer (2014-2017):

• Built CMS from scratch (.NET Core, Knockout.js, Entity Framework, Elasticsearch)
• Architected logging solution (shared library + cluster provisioning)
• Migrated entire user base from legacy to new platform
• Interim Tech Lead for 5 months
• Zero-downtime migration for public-facing infrastructure

Expert (daily use, 5+ years): C#, .NET Core/.NET 5-8, Entity Framework Proficient: Python, TypeScript, JavaScript, SQL, REST APIs, gRPC Familiar: Rust, C, OAuth, OIDC, FIDO2/CTAP Learning: WebAssembly, blockchain protocols

Expert: Docker, Git, GitHub Actions Proficient: Kubernetes, Rancher, ArgoCD, Harbor, TeamCity, Octopus Deploy Familiar: Azure (Service Bus, EntraID, S3)

Expert: SQL Server, Elasticsearch Proficient: PostgreSQL, Kibana, Logstash Familiar: Redis

• MCP (Model Context Protocol) and AI agent workflows
• Bitcoin and decentralized exchanges
• Rust → WebAssembly compilation
• Hardware authentication and secure enclaves

MCP server that lets AI assistants manage YubiKey operations. Instead of manual CLI commands, AI agents can discover devices, generate RSA keys on-hardware, configure touch policies, manage OATH/PIV/FIDO2 apps.

Built with FastMCP framework, translates JSON-RPC 2.0 MCP requests into ykman CLI operations. Supports Claude Code, VS Code, JetBrains IDEs.

Framework for building AI agent workflows with full MCP support. Makes it easy to iterate on agent architectures without tons of boilerplate.

Features:

• 5 workflow patterns (Chain, Parallel, Evaluator-Optimizer, Router, Orchestrator)
• Interactive debugging
• Swap between Anthropic (Claude) and OpenAI (GPT-4o, o1/o3) via flags
• Config-driven MCP servers
• Multi-modal (images/PDFs)

Conway's Game of Life in Rust compiled to WebAssembly. Sometimes you just need to watch patterns emerge at 60fps.

Personal blog and demo apps (Jekyll/HTML). Where I write about tech experiments and occasionally make things work in the browser.

Open source SDK with 117 stars, 59 forks. My day job, but also where I've contributed 120+ merged PRs. Enterprise authentication for .NET developers.

Forked/tracking:

• bisq (Java) - Decentralized Bitcoin exchange, exploring P2P trading infrastructure
• Bitcoin Core - Following development
• Hyperliquid DEX SDK - Current DeFi stuff

MCP ecosystem:

• Filed issues in Anthropic's claude-code and MCP python-sdk repos (protocol limitations, feature gaps)
• Active in discussions on MCP development
• Early adopter of Claude Code, Continue, and other agentic coding tools

Other interests:

• Bevy (Rust game engine)
• Anki (spaced repetition learning—yes I optimize how I learn)
• Open-WebUI, ChatterUI (LLM interfaces)

28 repositories | 52 starred repos | 120+ PRs merged in Yubico.NET.SDK | 75+ PR reviews | 25+ issues filed

Founded and chair Sweden's largest flow arts community, a non-profit spreading poi, staff, and fire spinning. Turns out coordinating flaming objects and developers need similar risk management skills.

BSc Computer Science & Software Engineering Stockholm University (2011-2014)

• Certified Scrum Master (2016)
• Kubernetes App Developer (2023)
• Elasticsearch Core Developer & Operations (2017)

Interested in companies pushing AI integration, blockchain infrastructure, and developer tooling.

Anthropic: Already engaged—filed issues in your repos, built two MCP servers, using Claude Code daily. I get MCP architecture (sampling, tools, resources) and bring security consciousness from hardware auth work.

Block: Blockchain isn't just buzzwords for me. Forked Bisq, track Bitcoin Core, follow DEX infrastructure. Your mission around economic empowerment and open financial systems aligns with what I care about.

Similar companies: Already using AI agents for code reviews, docs, workflow automation. I understand what developers need because I am one.

What I'm looking for:

• Building dev tools that don't suck
• Making security accessible
• Open source communities solving real problems
• Mission-driven work
• Remote-friendly (occasional work from abroad would be nice)

What I bring:

• 11 years shipping systems that work
• Open source experience (120+ PRs authored, 75+ reviewed)
• Mentorship (code reviews on security, architecture, knowledge sharing)
• Cross-platform dev (Windows/macOS/Linux/Android)
• MCP understanding (two production servers built)
• Security background (FIDO2/CTAP, crypto signing, hardware tokens)
• Agile delivery (Scrum Master, led teams through migrations)
• Communication (technical writing, stakeholder management)

Reach out:

• Signal: @moonkin88.88
• LinkedIn: in/dennis-dyallo
• Linktree: linktr.ee/dyallo (all my links)
• Portfolio: dennisdyallo.github.io
• GitHub: You're already here

"Debugging is like being a detective in a crime movie where you're also the murderer." — Filipe Fortes I write tests so my future self doesn't hunt down my past self.