Systems Engineer (Contract, Buenos Aires)

About Nexus

Nexus is building the foundation for verifiable finance, an economic system where every transaction, order, and settlement can be proven on-chain with cryptographic assurance. To do this we’re developing a DEX Layer 1 blockchain purpose-built for the AI economy, powered by idle compute from millions of people around the world, and verified with zero-knowledge proofs. This is finance rebuilt for the future: verifiable, scalable, and open to all.

Nexus has raised $25M in Series A funding from Lightspeed, Pantera, Dragonfly, SV Angel, and more.

Location: Remote (commutable distance to Buenos Aires)

Type: Contract

Duration: 12 months with potential for extension

The Role

We’re hiring Systems Engineers in Latin America to work at the core of Nexus’s execution stack — contributing to the runtime behind our Layer 1 protocol and the high-performance engine that powers decentralized trading.

This is not a typical backend role. You’ll design, implement, and optimize all layers of the Nexus protocol stack — including consensus, execution, and API/RPC servers — while helping define new financial and trading primitives on the Nexus L1.

You’ll work on performance-critical systems where microseconds matter, building execution paths that may evolve into core protocol primitives. Whether you’re a strong mid-level engineer ready to grow into system ownership or a senior/principal engineer eager to architect high-throughput distributed systems, this role offers the opportunity to build software that runs at the heart of a global execution layer.

You’ll collaborate closely with protocol, cryptography, and product teams in San Francisco while contributing remotely from Argentina.

What You’ll Do

• Design, implement, and optimize high-performance components in Rust, C++, or Go for Nexus’s DEX engine and protocol runtime.
• Design, implement, and optimize all layers of the Nexus protocol stack, including consensus, execution, and API/RPC servers.
• Build low-latency pipelines for order execution, event propagation, and state updates.
• Design and implement financial and trading primitives on the Nexus L.
• Optimize concurrency, scheduling, memory layout, and I/O paths for determinism and throughput.
• Contribute to the evolution of execution abstractions that may be enshrined at the protocol layer.
• Work with protocol engineers to ensure safety, composability, and consensus compatibility.
• Investigate and resolve performance bottlenecks using profiling, tracing, and benchmarking techniques.
• Help define standards for reliability, correctness, and high-assurance distributed execution.
• For senior/principal candidates: drive system design decisions, shape execution architecture, and mentor others in performance engineering.
  
  

What We’re Looking For

• Very strong systems engineering ability: writing modular, maintainable code within a complex codebase where correctness and performance are critical.
• Experience with Rust (or C++/Go with strong performance focus).
• Understanding of high-performance or distributed systems (e.g., low-latency engines, runtimes, databases, OS-level concurrency).
• Ability to think in terms of execution flows, concurrency models, resource lifecycles, and system invariants.
• Interest in performance optimization and low-level profiling (CPU, memory, synchronization overhead).
• Strong first-principles thinker with excellent problem-solving skills, attention to detail, and communication ability.
• Competitive programming experience (e.g., IOI, ICPC) or similar level of programming ability is a plus.
• Excellent communication skills in business English (spoken and written).
  
  

Bonus Points For

• Experience building matching engines, databases, compilers, blockchain runtimes, or HPC systems.
• Familiarity with lock-free concurrency, zero-copy data structures, or cache-aware design.
• Exposure to protocol engineering, consensus systems, or transaction ordering.
• Background in correctness-focused engineering (e.g., formal verification, static analysis).
• Open-source contributions to systems-level projects.
  
  

Why Join Us

• Build the execution backbone of a Layer 1 blockchain and next-generation DEX engine.
• Work on systems where your optimizations translate directly into global performance gains.
• Grow from mid-level contributor to system owner — or drive execution architecture as a senior/principal.
• Shape primitives designed to last — correct, performant, and potentially enshrined at the protocol level.
• Join a high-performance engineering culture where ambition and deep technical work are expected.