C++ game developer with Unreal and GAS experience

emagine is looking for a C++ game developer who will be working with Engine Performance in Unreal.

You will join a team working close to Unreal Engine on core tech and networked gameplay systems for our client. The team consists of senior engineers responsible for achieving performance targets across all platforms. You will focus on systems-level, code-driven optimization—especially for replicated gameplay and the Gameplay Ability System (GAS) across areas such as character movement, collisions, navigation, world streaming, and replication. Success in this role requires translating profiling insights into architectural and code changes, not just configuration or asset-level tweaks.

Start: ASAP
Length: 6 months with possible extension
Location: Stockholm, on-site 2–3 days per week (minimum)

Main Responsibilities:

• Analyze runtime performance using Unreal Insights and complementary tools; turn findings into code-level improvements (algorithms, data structures, threading, memory layout).

• Conduct root cause analyses for performance issues in networked gameplay paths; propose and implement mitigations such as refactors, caching, batching, async/off-thread work, or code-level LOD strategies.

• Profile and optimize high-cost systems including character movement, replication-heavy components, and GAS abilities; reduce per-frame and per-tick overhead, RPC frequency, and replication bandwidth.

• Assist gameplay and content teams in debugging performance bottlenecks; pair on instrumentation, budgets, perf gates, and trace capture to validate improvements.

• Review technical designs with attention to Unreal’s frame flow and update order; identify performance pitfalls early and recommend alternative architectures.

• Evolve the performance toolchain and workflows: extend tracing/markers, improve automated performance testing, and streamline triage/reporting.

• Champion performance best practices and knowledge sharing across engineering teams through documentation, brown-bags, and code reviews.

Key Requirements:

• 5+ years of professional C++ experience with strong understanding of language features, debugging, profiling, and systems architecture. Games experience strongly preferred.

• Production experience with Unreal Engine, including networked gameplay, and direct, hands-on experience optimizing the Gameplay Ability System (GAS).

• Proven track record of code-level performance improvements with concrete examples and before/after metrics—especially in character movement, replication (incl. Replication Graph/dormancy), ability execution, collisions/navigation, and AI update loops.

• Strong grasp of concurrency, memory, and performance optimization (tasks/async execution, lock contention, cache behavior, memory locality, data-oriented design).

• Clear understanding of Unreal’s runtime/frame flow and update order (tick groups, physics phases, networking/replication).

• Experience optimizing across multiple devices including consoles.

• Excellent problem-solving skills, collaborative mindset, and ability to lead complex, multi-domain investigations end-to-end.

Nice to Have:

• Familiarity with profiling tools such as Unreal Insights, Stat/CSV Profiler, NetProfiler, PIX, Superluminal, Tracy.

• Experience designing efficient replication strategies (Replication Graph, relevancy/dormancy), bandwidth/RPC optimization, client prediction and reconciliation.

• Hands-on work improving navigation, collision performance, world streaming, and tick reduction strategies.

• Experience with automated performance tests, CI perf gates, and dashboards.

• Knowledge of scalable GAS patterns (reducing per-tick logic, event-driven triggers, batching tag queries).