The Real Language and Tooling Shift in Quant Trading Engineering
The technical stack behind trading systems doesn't stay still for long. Based on what we're seeing across current client requirements and candidate conversations, a few clear shifts are worth understanding if you're either hiring for these roles or considering a move into this space.
Is C++ still the dominant language for trading systems engineering?
Yes, modern C++, specifically C++20 and C++23, remains the core language for execution engines and the lowest-latency parts of the stack. That hasn't changed. What has changed is what's increasingly expected alongside it.
Is Rust actually being adopted, or is it still mostly experimental?
It's moving well beyond experimental. Rust is increasingly listed as a genuine requirement, not a nice-to-have, particularly for real-time market data streaming and systems that need to interoperate across multiple language runtimes. Firms building new market data infrastructure or high-throughput streaming pipelines are specifically looking for candidates with real Rust experience, alongside C++, rather than treating it as a purely experimental or side-project language.
Has Python's role in quant trading actually changed, or is it still mainly used for scripting?
It's changed significantly. High-performance Python, using tools like PyTorch for machine learning workloads and Polars for fast dataframe operations, alongside GPU acceleration, has become genuinely mandatory for quantitative research and trading pods, not just a convenient scripting layer around a C++ core. **James Lancer, Team Lead at Reload**, puts it plainly: "Interviews for these roles aren't testing memorised algorithms anymore. It's walking through how you actually use PyTorch, how you train models on GPUs, and how you optimise them against genuinely large datasets."
Are firms actively moving away from older, legacy trading languages?
In some cases, yes, and it's a genuine hiring signal worth knowing about. Several firms with older, proprietary scripting languages built for specific trading systems are actively migrating toward Python for newer systematic strategy development. For engineers with legacy language experience, this is worth watching, since it signals where genuine modernisation hiring demand is likely to show up next.
What does this mean practically for engineers considering a move into this space right now?
Modern C++ remains the safest core skill to have, but it's no longer sufficient on its own for the most in-demand roles. Engineers who pair strong C++ fundamentals with genuine Rust experience, or who can demonstrate real, hands-on high-performance Python and ML tooling experience rather than basic scripting familiarity, are positioned for a noticeably wider set of opportunities than someone with C++ alone.
