Senior Unreal / Multiplayer Engineer

Mission: Build reliable multiplayer shared sessions, collaboration, reconnection, synchronization, and acceptable performance inside Wonderland.

  • Founding-Team Interest
  • Remote (United States)
  • 0.75% proposed equity
  • No visa sponsorship

Founding-Team Interest — Equity-Based Opportunity. i.Wonder Laboratories is currently identifying prospective founding-team members. Cash salaries have not yet been established. These listings are expressions of interest in future positions, not offers to begin unpaid employment. Any work arrangement will require a legally compliant agreement. Future team members are expected to make a serious time commitment once employment arrangements are finalized.

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The role

Build what makes Wonderland work with more than one person in it: shared sessions, collaboration, reconnection, synchronization and the performance that makes all of it feel solid.

What you’ll do

  • Build Wonderland’s multiplayer architecture in Unreal Engine: creating and joining sessions, shared world state, and the rules for who can see and change what.
  • Build collaboration so several creators — and the AI companions and agents working with them — can act in the same space and on the same project without conflicting.
  • Make reconnection robust: a client that drops should be able to return to its session and resynchronize without corrupting shared state or disrupting other players.
  • Design replication and synchronization for gameplay and creation state: what replicates, how often, with whose authority, and how conflicts resolve.
  • Profile and optimize CPU, GPU, memory and network bandwidth so shared sessions hold acceptable frame times and latency.
  • Build the tooling that makes multiplayer debuggable: multi-client test setups, network emulation (latency and packet loss), logging, and ways to reproduce desyncs.
  • Work with the backend engineer on the boundary between in-engine session state and durable server-side account and project data.

The technical challenges

  • Keeping a persistent, editable world consistent across clients while people and agents change it at the same time.
  • Reconnection and late joining when the world and project state are large.
  • Holding performance steady as worlds, creations and participants grow.
  • Turning intermittent multiplayer bugs into reproducible, automated tests.

What success looks like

  • Two or more players can reliably create, join, leave and rejoin a shared Wonderland session, and the shared state stays consistent.
  • Disconnects recover cleanly without losing or corrupting shared work.
  • Multiplayer performance is measured with repeatable benchmarks against agreed budgets.
  • Multiplayer defects are reproduced in an automated multi-client test before they are fixed.

Required qualifications

  • Professional experience building multiplayer software in Unreal Engine (UE4 or UE5) with C++.
  • Deep understanding of Unreal’s networking model: replication, RPCs, relevancy, ownership and authority, prediction and reconciliation.
  • Experience designing multiplayer architecture and session lifecycle, including join, leave and reconnection.
  • A track record of profiling and optimizing performance with tools such as Unreal Insights, the network profiler or platform profilers.
  • Methodical debugging of race conditions, desyncs and state corruption across multiple clients.
  • Ability to work independently in a small, early-stage team and to communicate clearly in writing.

Preferred qualifications

None of these are required.

  • Experience with Epic Online Services, Steamworks or similar services for sessions, lobbies and identity.
  • Shipped games or tools with user-generated content, building systems or persistent worlds.
  • Experience with Unreal’s Iris replication system, the Replication Graph, or dedicated-server deployment.
  • Automated multi-client testing and continuous integration for game builds.
  • Interest in AI-assisted creation and agent systems.

About i.Wonder

i.Wonder Laboratories, Inc. builds multiplayer open-world AI creation platforms, and researches, develops and deploys Compound AI Systems and Compound AI Agents. Our thesis is that AI creation should not end when a chat window closes: people and Compound AI Agents should be able to build, collaborate, compete, create software and maintain what they make, together, over time, inside a persistent world.

Wonderland is our flagship platform: a persistent multiplayer open world for AI creation, designed so that AI-powered creation and real software development happen in the same place as collaboration, competition and play. Wonderland is in active development.

Julius is our flagship Compound AI Agent and the intelligence inside Wonderland. It governs three permanent tiers — a Prompt Architect (a large language model), a Coding Agent (an agentic coding system) and an Independent Reviewer (an independent agent harness) — and every tier reads from and writes to Project Brain, Julius’s durable memory. Work is finished when independent review and verification say so, not when an agent says it is.

Read the research papers · Watch the Wonderland simulation

What to know about this stage

i.Wonder is an early-stage company. Wonderland and Julius are in active development, and the descriptions of them here are their intended design, not a report of finished features. The research papers set out the architecture and the evidence still to be gathered.

How to apply

Apply online with the application form. You’ll upload your résumé (PDF or DOCX), add your LinkedIn profile and links to relevant work — for example shipped projects, repositories, a portfolio or writing — and answer two short questions about this role.