Games Developer (Slots) AI-Native Game Development in London

Arena is a fast-moving digital entertainment company operating since 2021, with brands including MetaWin, WOW Vegas, BetZoo Media, Hit.com and Rolla, and teams across London, Malta, Gibraltar and Miami. We combine the agility of a startup with the scale of a high-growth technology company.

Gladiator Games Studio was founded by people who have spent 16+ years building top-performing slots. We're now rebuilding how those games get made.

We build HTML5 slots - Legend of Tartarus, Candy Cash, Rise of Cetus and the titles behind them on our own PIXI/TypeScript framework, integrated with our game servers over REST and WebSocket. This is a front-end games role, and the craft still matters: reel mechanics, animation timing, game feel, 60fps on a mid-range phone. But we're not hiring someone to hand-write the twentieth version of a paytable loader. Slot development is unusually repetitive; every title reuses the same framework, the same reel and win-evaluation patterns, the same config shapes, the same asset pipeline and that repetition is exactly where AI agents earn their keep.

So we're looking for a developer who codes with agents rather than around them: someone who can take a maths spec and a set of assets and get to a playable build far faster than a traditional workflow allows, because they've built the harness that makes it possible. This is a 0→1 opportunity on the AI side. We have Claude in the workflow and real appetite from leadership, but the agent tooling for our studio - the repo conventions, the MCP integrations to our maths specs and asset pipeline, the generation and review loops, the evals that stop an agent quietly breaking win evaluation - is still to be built. If you've done this before somewhere else and want to do it properly this time, this is that job.

What you'll do

• Build slot games.
• Design, build and maintain our multi-platform slots framework, mobile-first, in TypeScript and PIXI.js.
• Ship new titles end to end: reel mechanics, win evaluation, bonus rounds, free spins, multiplier ladders, feature buys and big-win presentation.
• Integrate with our game servers over REST and WebSocket, and make the client behave correctly when the network doesn't reconnects, resumed sessions, interrupted rounds.
• Optimise hard: draw calls, texture atlases, memory pressure, load times and steady framerate on real mid-range devices, not just your laptop.
• Build fast prototypes for game designers so a mechanic can be felt before it's committed to.
• Enforce the boring things that keep a studio fast: clean module boundaries, code review, testing standards, documentation another developer can actually use.
• Build the AI workflow (0→1).
• Own how this studio develops games with AI - the tooling, the conventions and the practice and take it from where it is now to something the whole team works inside.
• Make the codebase agent-legible: project instructions, structured conventions, clear seams and typed contracts so an agent can make a correct change without a human re-reading the whole framework.
• Build agent workflows for the repetitive 80% scaffolding a new title from the framework, turning a maths spec into config, wiring symbol atlases and animation timelines, generating tests, reskinning an existing mechanic for a new theme, migrating titles when the framework changes.
• Connect agents to our real systems: MCP integrations to maths specs, the asset pipeline, the game server API and our issue tracker, so the agent works from source of truth rather than guesses.
• Build the guardrails that make speed safe: automated evals, golden-master round tests, maths regression checks and review gates. Generated code that touches payouts gets verified, not trusted.
• Measure it honestly. Track where AI actually shortens the path from spec to playable build and where it doesn't, and kill what doesn't work.
• Bring the rest of the studio with you: patterns, prompts, examples and enough teaching that this becomes how the team works rather than your personal setup.

What we're looking for

• 3+ years professional experience building HTML5 browser-based slot games (or comparable real-time HTML5 game work), with proven PIXI.js and TypeScript depth.
• Strong JavaScript/TypeScript fundamentals, Node, and solid experience integrating REST APIs and WebSocket-driven game servers.
• Agent-level AI coding, not autocomplete. You work with coding agents on real, multi-file changes (Claude Code, Codex, Cursor agents or equivalent) and you understand how to structure a task, a repo and a review loop so the agent produces code you'd actually merge.
• Experience building an AI workflow from 0 to 1. You've set one up somewhere - project instructions and conventions, subagents or pipelines for repeated tasks, MCP or tool integrations, automated checks on generated output and can talk concretely about what you built, what it sped up, and what you had to throw away.
• A clear model of where AI makes game development faster and where it doesn't. Boilerplate, config, migrations and tests: yes. Game feel, animation timing, performance tuning and payout maths: only under verification.
• Cross-browser and multi-device competence, plus the profiling skills to find out why it's dropping frames instead of guessing.
• Clean, maintainable code and the judgement to keep a framework consistent across many titles.
• Fluent English and the ability to work with designers, maths and QA without a translator.

What will set you apart

• You've shipped a real production feature or title where agents did a meaningful share of the work, and you can explain the review and testing that made that safe.
• Custom agent tooling: MCP servers, subagent pipelines, evals or benchmark harnesses, CI that runs against agent output.
• Slot maths literacy: RTP, volatility, paytables, hit frequency and enough respect for it to never let an agent near it unchecked.
• Framework or engine authorship: you've built the thing other developers build on.
• WebGL/shader work, Spine or Rive animation, or serious asset-pipeline automation.
• Crypto or real-money product experience, or provably-fair mechanics.
• An interest in the next step: agents that build, test and iterate a title with a developer supervising rather than typing.

We care more about how you think and how fast you learn than about a checklist. This field is changing every few months; we want someone who's visibly keeping up.

Tech stack: TypeScript · PIXI.js · HTML5 · Node · REST · WebSocket · Git · Claude Code and the AI tooling you bring with you.

What we offer

• A genuine 0→1 mandate on AI-native game development, with leadership backing and no legacy process defending itself.
• A studio founded by people who've shipped top-performing slots for 16+ years - craft and speed, not one at the expense of the other.
• Competitive salary, 20 days annual leave plus 8 bank holidays.
• Modern central London workspace, PS5, fruit, drinks, snacks and beer in the office, bicycle parking.
• Company socials, outings and recognition programmes.