Systems Software Engineer (Rust)

ai-coustics is building the reliability layer for Voice AI, the system that closes the gap between raw audio input and reliable machine understanding in production. By combining state-of-the-art speech and audio research with real-time, production-grade SDKs, we test, observe, and enable Voice AI systems to work in any environment. Our software is used by fast-growing Voice AI
companies across Europe and the United States whose products require reliable performance at scale: call center agents, voice agents, telephony apps, and enterprise voice assistants. We believe voice will become the main interface for technology and ai-coustics is building the foundational infrastructure to make audio input reliable, measurable, and easy to deploy.

We are backed by leading early-stage investors including Connect Ventures, Partech, Inovia Capital , as well as angel investors from HuggingFace, DeepMind and Amazon with deep expertise in AI and developer infrastructure. These partners share our vision and are helping us build a world-class team operating with high levels of responsibility and velocity . We look for people who take ownership, think systemically, and want to solve challenging real-world problems in close collaboration with our customers. If you’re motivated by developing technology that is used in practice, shaping an emerging category and setting a new standard for how voice AI works in the real world, you’ll feel at home at ai-coustics.

Tasks

Core SDK & Runtime Development

• Design, implement, and optimize systems-level components of the ai-coustics SDK
• Improve the performance, memory usage, and stability of the Airten real-time inference engine
• Develop and maintain DSP modules and supporting audio-processing infrastructure
• Contribute to the evolution of SDK APIs with a focus on ergonomics, safety, and long-term maintainability

Language Bindings & Platform Support

• Maintain and expand our C API and public C library generated from the our internal Rust codebase
• Improve and support SDK wrappers and bindings for C++, Python, and Rust (via the public C API)
• Maintain WASM and Node.js SDKs built directly from the internal Rust source
• Ensure consistent behavior, performance, and API guarantees across platforms

Testing, Reliability & Tooling

• Design, implement, and extend our testing pipeline , including unit tests, integration tests, and performance benchmarks
• Build tooling to validate real-time constraints , numerical correctness, and cross-language consistency
• Improve CI workflows to ensure safe and fast iteration on a closed-source core with public-facing SDKs

Telemetry & Observability

• Develop and improve the SDK’s telemetry and usage monitoring systems
• Ensure telemetry is performant, privacy-conscious, and reliable across environments
• Collaborate with product and infrastructure teams to turn telemetry into actionable insights

Documentation & Developer Experience

• Write and maintain high-quality technical documentation for SDK APIs, internals, and integration guides
• Collaborate with product and developer-facing teams to improve onboarding and usability
• Support internal teams and external developers by diagnosing SDK issues and proposing robust fixes

Requirements

Technical Skills

• Strong experience in systems programming , ideally with Rust
• Solid understanding of C/C++ interoperability , ABIs, and FFI design
• Experience building or maintaining SDKs, libraries, or runtimes used by external developers
• Familiarity with real-time systems , performance optimization, and memory management
• Experience writing tests and benchmarks for low-level or performance-critical code
• Comfortable working across multiple platforms (Linux, macOS, Windows, WASM)

Audio / ML Systems (Nice to Have)

• Experience with digital signal processing (DSP) or audio pipelines
• Familiarity with ML inference runtimes or deploying neural networks in production
• Exposure to real-time audio constraints (latency, jitter, streaming workloads)

Mindset & Collaboration

• Strong ownership mentality and attention to detail
• Comfortable working in a closed-source core with open SDK surfaces
• Ability to reason about trade-offs between performance, safety, and developer experience
• Clear written communication skills for documentation and technical design discussions
• Enjoys working in a fast-moving startup environment with real-world production impact

Benefits

• Opportunity to work at a rapidly growing Voice AI startup , backed by top investors.
• Compensation and equity: Competitive salary package, additional benefits and stock options, enabling you to take part in the company’s success.
• Startup Culture: Dynamic, fast-paced environment with passionate and collaborative colleagues.
• High Impact: Groundbreaking startup at a pivotal growth stage, making a real difference in how people experience audio.
• Ownership & Autonomy: Take full ownership of projects and ship fast.
• Work With the Best: World-class team of engineers and builders with ample room for professional growth.
• Contribute to the Future: Define the landscape of Voice AI technology.

If you are ready to lead the charge in revolutionizing Voice AI and drive our startup to new heights, we would love to hear from you. Apply today to join the ai-coustics team!