Senior Unreal Engine / Multiplayer Engineer (Founding-Team Interest, Equity Only)

Description

The company is at an early stage and is looking for prospective founding-team members. No cash salary has been set yet. This listing expresses interest in a future position and is not an offer to start work unpaid, and any work arrangement will need a legally compliant agreement.

The company, the company's site Laboratories, Inc., is building two connected products that are both in active development. Julius is a compound AI agent that runs missions through a Prompt Architect, a Coding Agent and an Independent Reviewer, all sharing Project Brain, a durable mission memory. Wonderland is a persistent multiplayer open world for AI creation, built in Unreal Engine, where people and their AI agents create, collaborate and build software together. The descriptions reflect intended design, not finished features.

The role is about keeping a persistent, editable Unreal Engine world consistent while several people and their AI agents change it at once, and letting anyone who disconnects rejoin without losing work.

Responsibilities

• Design Wonderland's multiplayer architecture in Unreal Engine 5 using C++, covering session lifecycle (create, join, leave, reconnect, late-join), shared world state, and who may view and modify what.
• Define replication and synchronization for gameplay and creation state: what replicates, how often, who holds authority, and how conflicts are resolved.
• Resynchronize returning clients on reconnection without corrupting shared state or disrupting other players.
• Bring AI agents and companions into the world as participants that work on shared projects alongside people.
• Set and track performance budgets for CPU, GPU, memory and bandwidth using repeatable benchmarks.
• Build multiplayer tooling: multi-client test setups, network emulation for latency and packet loss, logging, and automated tests that reproduce desyncs.
• Own, together with the backend engineer, the boundary between in-engine session state and durable server-side account and project data.

Requirements

• Professional multiplayer experience in Unreal Engine (UE4 or UE5) with C++.
• Deep understanding of Unreal networking, including replication, RPCs, relevancy, ownership and authority, and prediction and reconciliation.
• Experience designing session lifecycles, including join, leave and reconnection.
• Experience profiling with Unreal Insights, the network profiler or platform profilers.
• A methodical approach to debugging race conditions, desyncs and state corruption.
• Ability to work independently in a very small team and to write clearly.
• Interest in AI agents inside games.
• Useful but not required: experience with Iris, Replication Graph or dedicated-server deployment; Epic Online Services or Steamworks sessions and identity; shipped UGC, building or persistent-world systems; automated multi-client tests and CI for game builds.

Conditions

Proposed equity of 0.75%, vesting over four years with a one-year cliff. These are proposed terms, subject to final written agreements.

No cash salary has been established, so none is offered or implied.

Founding-team interest, remote within the United States. Visa sponsorship is not available. Future team members are expected to commit seriously in time once employment arrangements are finalized.

Applications are reviewed by a person. Submit a résumé, links to your work and short answers to a few questions through the Wellfound listing.

Benefits

• Equity: 0.75% proposed, with a four-year vesting schedule and a one-year cliff.