Harald Maassen
Engineering and Developer Relations Leader
I build technical teams and systems that help developers succeed.
Across nearly two decades in games and developer platforms, I've spent a decade as a hands-on programmer and nine years building and leading teams in developer support, developer relations, and developer experience.
At Improbable, I built a developer support function from the ground up. Epic Games subsequently hired the full team, and I continued leading it at Epic for four years, growing my team from four engineers to eight. I remain hands-on through independent browser-game projects exploring multiplayer systems, AI-assisted development, and runtime LLM integration.
Sometimes I design systems in code. Sometimes I design them in organizations.
Selected Highlights
- Built Improbable's developer support operation from zero, covering ticketing, on-call support, knowledge management, training, and recruitment.
- Led the same core team through fully remote work, company pivots, and an acquisition by Epic Games - retaining the full group throughout.
- One of three managers in Epic's ~25-engineer Developer Relations org; grew my own team from four to eight engineers, with support CSAT above 4.8/5.
- Created an Unreal Engine developer-success program combining proactive outreach, technical content, studio visits, and release tracking.
- Shipped commercial games across PlayStation 3, Xbox 360, Nintendo 3DS, iOS, Android, and Windows Phone.
- Currently building multiplayer browser games with Claude Code as part of my daily development workflow.
Leadership Experience
Epic Games
Epic hired the developer-support team I had led at Improbable, and I continued managing it for another four years as one of three managers in a ~25-engineer Developer Relations org. My team grew from four to eight engineers - with full hiring and performance ownership - while I integrated a fully remote, acquired group into Epic's organization and working culture.
The team supported developers across Epic's ecosystem, combining reactive technical support - where CSAT held above 4.8/5 - with an increasing focus on proactive developer success.
No Bad Games
I created and led "No Bad Games," an Unreal Engine developer-success program designed to identify release risks and help studios achieve better technical outcomes. It combined proactive outreach to development teams, on-site studio visits, performance and optimization content, release tracking and post-mortems, and playbooks for recurring engagement scenarios.
The release tracking - around 100 releases a year - exposed common technical problems behind difficult launches and gave teams a shared way to measure and discuss them. Proactive performance reviews with studios grew tenfold, from a handful a year to multiple every month, and the team published a dozen in-depth performance tutorials and guides for the developer community - all alongside the regular support work.
Organizational Design
I also designed a guild structure for teams working across Epic's matrix organization. These cross-team communities of practice created clearer professional connections, improved knowledge-sharing, and gave specialists a forum beyond their immediate reporting lines.
Improbable
I joined Improbable as a support engineer helping game studios build on SpatialOS, its distributed multiplayer development platform. I later moved into engineering management and became Head of Support in 2020, building and running the support operation end to end: ticketing and escalation processes, on-call rotas, knowledge management, internal training, recruitment, and performance management.
I led the team through the transition to fully remote work and several changes in company direction while retaining the full group and maintaining service quality.
Epic Online Services
The team later took on third-party developer support for Epic Online Services, Epic's cross-platform SDK and backend services. A team of four handled around 30 forum questions a day - answering every single one, including complex technical investigations conducted in partnership with Epic's engineers.
Epic subsequently hired the full team, and I continued managing and growing it inside Epic Games.
King
Features for Farm Heroes Saga, a custom audio plugin, and reverse-engineering King's legacy internal game engine - work that produced a detailed architectural report documenting its structure and constraints for future teams.
Codeglue
Nearly eight years developing games across PlayStation 3, Xbox 360, Nintendo 3DS, mobile, and other platforms: gameplay systems, physics, multiplayer networking, rendering, platform ports, and technical leadership. Highlights below.
How I Lead Teams
Build around people
I've created secondments and cross-team placements to help people move into work better suited to their strengths, and coached individual contributors into product-management and project-management careers - including cases where that meant losing strong people from my own team.
Address difficult issues early
Direct feedback, clear expectations, and structured support. That includes handling underperformance through improvement plans while protecting trust and morale across the wider team.
Design for change
The same core group stayed together for more than four years through a pandemic, multiple company pivots, fully remote work, and an acquisition. That stability came from clear communication, strong working relationships, and giving people useful context during uncertain periods.
Treat remote work as an operating model
I've hired, onboarded, integrated, and grown teams without relying on a shared office. Remote leadership requires deliberate communication, visible decision-making, strong documentation, and opportunities for informal professional connection.
Use process to create clarity
I use tools such as SMART goals, RACI, MOCHA, and structured feedback cycles when they solve a specific problem. Process should reduce ambiguity, not become an end in itself. I'm a big fan of the Manager Tools folks - Mark Horstman's talk "What You've Been Taught About Management is Wrong" is a good taste of where much of this thinking comes from.
Independent Technical Work
My independent projects are a practical laboratory for AI-assisted development, multiplayer systems, and browser-based game technology. Claude Code is part of my daily workflow - implementation, investigation, refactoring, testing - and I experiment with runtime LLM systems and local diffusion pipelines for game assets. I write about what actually works on my dev blog.
The projects are collected in Meridian, a small launcher I built for them:
ProtoFighter
Rollback networking and AI-assisted animation
A browser-based 2D fighting game inspired by Street Fighter, combining two technical experiments: generating game-ready sprite animations from a single character image using a local diffusion pipeline, and implementing GGPO-style rollback netcode in a browser-only stack.
Deterministic TypeScript simulation, PixiJS rendering, peer-to-peer WebRTC multiplayer, and a lightweight Python signalling server. Nothing to install: players open a link and start a match.
Legends of Amara
Agent-assisted development and runtime LLM systems
A multiplayer browser dungeon crawler inspired by classic Zelda games, built largely with Claude Code acting as a development agent. LLMs are also part of the game itself: they generate dungeons and monsters dynamically, while NPCs hold natural-language conversations shaped by their personalities, goals, and roles in the world.
The project explores the distinction between using AI to build a game and using AI as part of the game's runtime design.
Revenge of the Evil Aliens: Revenged Edition
Decompilation, legacy recovery, and WebAssembly
Revenge of the Evil Aliens began as an XNA side project in 2008 - it helped me secure my first professional game-development role, but its original source code was later lost. I recovered the released Xbox 360 package, decompiled its .NET bytecode into roughly 40,000 lines of C#, ported it to KNI (an XNA-compatible framework supporting WebAssembly and WebGL), and updated its graphics and gameplay.
The result is an Xbox 360 game from 2008 running in a modern browser.
Selected Games
Before moving into management, I spent a decade programming commercial games. Two highlights:
ibb & obb (2013 · C++ · PS3)
Responsible for roughly 90% of the programming on this co-op puzzle platformer:
- A stable 2D physics system supporting gravity reversal, plus custom shaders on Sony PhyreEngine
- Peer-to-peer multiplayer with prediction, interpolation, and authority reconciliation - the networking had to support close physical interactions between players (standing on each other, pushing, grabbing)
- Technical leadership for interns and freelance contributors
Terraria (C++ · 3DS / iOS / Android / WP8)
Codeglue rewrote Terraria's C# codebase in C++ for its mobile and handheld ports. I contributed across the project, with a focus on gameplay and the Nintendo 3DS version: mobile-exclusive seasonal bosses, stylus input, redesigned menus, and rendering optimizations for the hardware.
Other shipped titles include Rocket Riot (Xbox LIVE Arcade / WP7), Hydro Tilt (iPhone), and the Antegods prototype. I also love game jams - favorites: Wob Wob (adaptive audio, 2nd place) and Kipp (XNA, audience award).
Beyond Work
Five published D&D products on DMsGuild, including Old School Guide to Dungeon of the Mad Mage and Heist on Cassalanter Villa. Co-host and editor of Blazing Bastards (▶), a Dutch D&D actual play podcast. More on the blog.
