Backend Engineer (AI, Rust)

TL;DR

Backend Engineer (AI, Rust): Designing and building high-scale, low-latency backend services in Rust for an AI safety platform with an accent on real-time policy checks, API design, and database performance. Focus on owning features end-to-end, improving system reliability, and collaborating with product and ML teams.

Location: Hybrid in Paris, France. A relocation package is offered.

Salary: $80,000–$150,000 + equity

Company

White Circle is an AI Safety company focused on building safety, reliability, and optimization layers for AI systems, backed by $11M in funding.

What you will do

• Design and build high-scale, low-latency backend services in Rust for real-time AI policy checks.
• Own features from API design to database schema and deployment, monitoring, and iteration.
• Improve system performance and reliability through connection pooling, caching, and query optimization.
• Collaborate with product, research, and ML teams to translate requirements into production systems.
• Work across the full stack when necessary to solve problems.

Requirements

• Proven experience building and shipping backend systems in Rust, not just tutorials.
• Comfortable with async Rust (Tokio), web frameworks (Axum, Actix), and database access patterns.
• Strong fundamentals in system design, including reasoning about trade-offs and scaling.
• Experience with PostgreSQL, efficient queries, schema design, and debugging.
• Fluent English for clear communication and collaboration.
• Must be able to work hybrid in Paris, France.

Nice to have

• Experience with ClickHouse, Redis, or Kafka/event streaming.
• Familiarity with Kubernetes and infrastructure-as-code (Terraform, Helm).
• Background in high-throughput systems monitoring or fintech.

Culture & Benefits

• 20 days of paid vacation.
• Comprehensive medical insurance in France.
• All necessary hardware, tools, and covered subscriptions for AI agents and IDEs.
• Regular team off-sites (e.g., Alps, Saint-Tropez).
• Opportunity to work on hard problems with a small, focused team and see work ship quickly.