Software Engineer (Rust) | BTG Empresas

Description

Job Summary: Senior technical implementer to develop a proprietary HAL in Rust, eliminating dependency on external vendors for POS terminals, with a focus on critical performance and embedded systems. Key Highlights: 1. Lead the transformation of the financial system with our proprietary HAL 2. Develop in Rust for a high-performance payment micro-kernel 3. Autonomy to choose data structures and low-level optimizations **About the Team:** At BTG Empresas, you will be the senior technical implementer for one of the largest transformations in the Brazilian financial system: the creation of a proprietary HAL (Hardware Abstraction Layer) that will eliminate our dependency on third-party vendors for POS terminals. **Your Day-to-Day Responsibilities:** * Hands-on implementation of the BTG HAL Library core in Rust, executing the already-defined multi-vendor architecture; * Develop a payment micro-kernel with critical performance (2ms overhead) for EMV processing; * Create multi-vendor adapters abstracting differences among manufacturers (PAX, Sunmi, Positivo); * Implement complex FFI bridges: Rust ↔ Flutter/Dart (capture software) and Rust ↔ C/Java (L2 vendor libraries); * Develop efficient serialization for cross-language communication while maintaining performance targets; * Integrate with native C/Java L2 vendor libraries, adapting varying API signatures; * Optimize performance of critical operations targeting ARM Cortex-A53 embedded systems; * Exercise autonomy in selecting data structures, algorithms, and low-level optimizations; * Validate implementations through rigorous benchmarks and testing on real terminals; * Collaborate intensively via pair programming with the Principal HAL Engineer and other Rust developers. **What We Expect From You:** * Bachelor's degree in Engineering, Computer Science, or related fields; * Availability for on-site work in São Paulo/SP; experience in C/C++ systems programming OR advanced Rust experience focused on critical performance; * Solid experience with FFI and cross-language interoperability (C↔Java/JNI, C++↔Kotlin, Rust↔C, Rust↔Dart, etc.); * Expertise in efficient serialization: JSON, MessagePack, Protocol Buffers, or similar technologies with a performance focus; * Deep knowledge of concurrent programming: threads, mutexes, atomic operations, async patterns, performance tuning; * Background in embedded systems, mobile, or real-time systems: memory management, resource constraints, ARM optimization; * Experience with build systems and cross-compilation: Make/CMake, Cargo, CI/CD for multiple targets; * Proficiency in debugging and profiling high-performance applications in production environments; * Expertise in system design: hardware abstraction layers, plugin architectures, cross-platform API design; * Memory management expertise: manual memory management, ownership patterns, performance optimization; * Systemic thinking for low-level optimizations with architectural impact; * Ability to engage in intensive pair programming and technical collaboration with other developers. **Technical Differentiators:** * Prior experience with payment processing or mission-critical financial systems; * Background in developing C/C++ or Rust open-source libraries, frameworks, or drivers; * Advanced serialization: experience with FlatBuffers, Cap'n Proto, or other zero-copy technologies; * Flutter/Dart interop: experience with platform channels, dart:ffi, or native mobile integration; * For C/C++ profiles: experience with game engines (Unreal, Unity C++), compilers, database engines, or networking stacks; * For Rust profiles: background in async/await, ownership model, Cargo ecosystem, tokio/serde; * Knowledge of Android NDK and native integration (C++↔Kotlin, Rust↔Android via JNI); * Experience with POS terminals, embedded systems, real-time systems, or hardware-constrained environments; * Background in optimization: SIMD, cache optimization, profiling tools (perf, valgrind, heaptrack); * Multi-language architecture: experience orchestrating 3+ languages in a mission-critical project. **Benefits:** * Profit and Results Sharing Program (PLR); * Meal and Food Allowance; * Health Insurance; * Dental Insurance; * Childcare/Babysitter Assistance; * Transportation Voucher; * WellHub; * TotalPass; * Personal Support Program (EAP); * Optional plans such as Private Pension and Life Insurance; * Pharmacy Discount; * Nutrition Program; * Pregnancy Program; * Extended Maternity and Paternity Leave – Certified Citizen Company.