Product Engineer, Backend (Rust)

Npv; Paris; On-site; EUR 69,000 - 129,000; Full time

Benefits offered by this job

Equity

Relocation assistance

Visa sponsorship

Job summary

White Circle, an AI Safety company, is hiring a Product Engineer, Backend (Rust) to design and build high-scale Rust services that perform real-time policy checks. You will own features end-to-end, including API design, data schemas, deployment, and monitoring.

You will collaborate with product and research to improve performance, reliability, and observability, using connection pooling, caching, and query optimization. Relocation to Paris or London is required, with hybrid work.

Qualifications

• Production experience with Rust, Python, or Go.
• Experience with async Rust (Tokio) and Axum/Actix.
• Strong system design fundamentals and scaling.
• Willingness to relocate to Paris or London and work hybrid.

Responsibilities

• Design and build Rust backend services handling real-time policy checks at scale.
• Own features end-to-end – API design, schema, deployment, monitoring.
• Improve performance and reliability through connection pooling, caching, query optimization, and observability.
• Collaborate directly with product and research.

Skills

Rust

Python

Go

Async Rust (Tokio)

Axum/Actix

PostgreSQL

System design

Tools

PostgreSQL

Job description

We're looking for a Product Engineer, Backend (Rust) to join White Circle, an AI Safety company building the policy enforcement and optimization layer for AI systems. Backed by $11M from senior leaders at OpenAI, Anthropic, HuggingFace, Mistral, and DeepMind, White Circle processes 100M+ API calls monthly and runs its own LLMs in production.

You will

• Design and build Rust backend services handling real-time policy checks at scale.

• Own features end-to-end – API design, schema, deployment, monitoring.

• Improve performance and reliability through connection pooling, caching, query optimization, and observability.

• Collaborate directly with product and research.

Requirements

• Production experience with Rust, Python, or Go.

• Comfortable with async Rust (Tokio), Axum/Actix, and PostgreSQL – schema design, query optimization, debugging.

• Strong system design fundamentals: trade-offs, failure modes, scaling.

• Relocation to Paris or London (hybrid) required.

Stack

• Rust, Tokio, Axum/Actix, PostgreSQL.

• Bonus: ClickHouse, Redis, Kafka, LLM infra (routing, inference, RAG), or high-throughput monitoring background.

We offer

• $80k–$150k/year salary + equity; higher figures can be negotiated.

• Official employment, visa and relocation help.

Compensation

Compensation: $80K – $150K Higher figures and equity are negotiable