Gameplay Network Engineer - C++, Unreal Engine (Replication / RPC)
About Steel City Interactive
SCI was born out of passion for video games and boxing, with the ambition to create an authentic and exciting boxing game that does justice to the sport we love. What started as a fun prototype has grown into ‘Undisputed’, the first major boxing video game in over a decade.
SCI is a welcoming place for expression and open communication, where everyone has a voice. We’re a diverse bunch, consisting of people with decades of games industry experience, graduates and talented individuals who come from other industries. We all bring knowledge and learn from each other.
Together we are driven by ambition to bring the world of boxing into a video game like never before.
**No Visa Support or transfer available for this role **
Flexible work options, onsite (Sheffield or Leamington Spa), hybrid or remote (UK only)
The Role
You are an experienced, mid level, Gameplay Network Engineer with a strong focus on implementing and optimising replication systems, with experience working on multiplayer titles in Unreal Engine using C++. You’re comfortable working within established networking architectures, contributing to the performance, reliability, and correctness of networked gameplay systems.
We’re looking for a talented Engineer to help shape the future of our multiplayer boxing game, Undisputed. As we move to UE5, you’ll play a key role in building, refining, and optimising replication systems to support fast, responsive two-player gameplay while maintaining AAA quality. The game uses a peer-to-peer networking model, requiring thoughtful handling of latency, synchronization, and state consistency between clients.
You’ll work closely with a highly skilled, diverse team to deliver world-class networked gameplay, with a hands-on focus on replication performance and stability, and ownership of features through integration, iteration, and ongoing support.
Responsibilities
· Implement, maintain, and optimise network systems, with a focus on Unreal Engine’s replication framework and runtime performance.
· Improve replication efficiency, correctness, and bandwidth usage within existing systems.
· Optimise network data transmission to minimise latency, focusing on efficient handling of player inputs to drive responsive character movement and interactions.
· Collaborate with gameplay and server teams to integrate networked systems with physics and animation pipelines, ensuring stable and consistent state synchronisation across clients, with clear runtime contracts between systems.
· Implement and refine replication techniques such as prioritisation, delta compression, and prediction to support responsive multiplayer gameplay, with a focus on measurable improvements.
· Debug and resolve network-related issues, including desyncs, packet loss, and latency spikes, using profiling and debugging tools, and contribute fixes that improve overall system robustness.
· Optimise network performance for cross-platform play (console and PC), ensuring reliability under a range of network conditions.
· Contribute to code reviews, best practices, and technical documentation, producing clear and maintainable code and supporting shared understanding across the team.
· Stay up to date with Unreal Engine networking developments and relevant multiplayer technologies.
Knowledge, Skills & Experience
· Experience in gameplay network programming within Unreal Engine, using C++ as a primary language.
· Strong understanding of Unreal Engine’s networking architecture, including replication and RPCs, with hands-on experience implementing and optimising systems in production.
· Experience with Unreal Engine 4 or 5 networking tools and pipelines.
· Solid understanding of network protocols (e.g. UDP, TCP) and techniques for optimising real-time game data.
· Experience debugging, profiling, and optimising networked systems for low-latency gameplay, including identifying root causes of desyncs and synchronisation issues.
· Strong understanding of 3D maths, data structures, and multiplayer synchronisation techniques.
· Solid grasp of software architecture and engineering best practices, applied to maintain stability and scalability.
· Good communication and documentation skills, with the ability to work effectively with gameplay engineers and technical designers and clearly explain constraints and trade-offs.
· Self-driven, proactive, and detail-oriented.
· Experience with rollback Netcode is a plus.
· Experience working on competitive multiplayer titles is beneficial.
What we Offer
Healthy work-life balance:
23 days annual leave (plus bank holidays), that increases 1 day per year of service, up to a maximum of 30 days.
Christmas shut down
Holiday exchange programme
Flexible working hours & pattern (Certain Hybrid models available)
Support for family life:
Enhanced Maternity and Paternity pay (subject to eligibility requirements)
Private Healthcare which includes Optical & Dental
Great office environment:
Friendly studios based in Sheffield and Leamington, with free snacks, fruit and drinks!
Free parking - At our Sheffield site
Health & wellbeing support:
Company sick pay
2 days Wellbeing Days leave per year
Access to 24/7 doctors
Employee Assistance Programme
Learning support:
Learning days
Additional financial support:
Technology scheme (salary sacrifice up to £750)
Relocation benefits (subject to eligibility requirements)
Electric Car Vehicle Scheme (subject to eligibility requirements)
Discretionary Bonus
Connection and perks:
Wrap parties & company paid outings
Individual entertainment budget to cover team events
