Systems Engineer (Contract, Brazil)

**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 (Brazil) **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 Brazil. **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.