Distributed Systems Engineer

About Windmill

Open-source platform to turn scripts into internal apps & workflows

Tech

backend: Rust - stateless API servers + workers pulling jobs from a Postgres queue. Optimized for high-throughput job execution (~50ms overhead per job). frontend: Svelte 5 db: Postgres as the single source of truth (job queue, state, metadata). Compatible with Aurora, Cloud SQL, Neon. sandboxing: nsjail + PID namespace isolation. We run untrusted user code in 20+ languages (Bun, Python, Go, Bash, PowerShell, PHP, C#, Java, Ansible…) safely on shared workers. deploy: Docker / Helm. Runs on AWS, GCP, Azure, Hetzner, etc. Self-hosted by large enterprises.

The role

Work on Windmill's **Rust backend** - the execution engine, workers, language runtimes, API layer, and infrastructure that powers thousands of production deployments.* **Execution engine**: scheduling, job queues, worker orchestration, flow execution with branching, parallelism, retries, and error handling.* **Language runtimes**: maintain and extend sandboxed runtimes for Python, TypeScript, Go, Bash, SQL, and more.* **Performance & reliability**: profiling, optimization, resource management. Our users run mission-critical workloads - correctness and uptime matter.* **Infrastructure**: PostgreSQL schema design, caching, networking, deployment tooling.## **Who we're looking for****This is a senior role.** We're looking for someone who has operated distributed systems at scale and can teach us from day one - showing us PostgreSQL patterns, distributed systems techniques, and architectural improvements we haven't considered yet.* Proven experience building and operating **distributed systems at scale** - not theoretical, you've done it in production* Deep **PostgreSQL** expertise - query optimization, schema design, concurrency control, partitioning, replication. You know what breaks at scale and how to fix it.* Strong systems programming skills - **Rust** experience strongly preferred, otherwise C/C++ with willingness to switch* You bring opinions and techniques from previous infrastructure work that will make Windmill better immediately* You enjoy hard infrastructure problems and care about correctness### **Example projects in your first 3 months*** Redesign the job queue to handle bursty workloads with thousands of concurrent jobs without degrading scheduling latency* Implement a new worker orchestration strategy that improves resource utilization across heterogeneous deployments (2 to 600 workers)* Optimize critical PostgreSQL queries and schema for customers with millions of completed jobs - partitioning, indexing, vacuum tuning* Add a new language runtime (e.g., Java, C#) with proper sandboxing, dependency management, and execution feedback* Build observability tooling - distributed tracing across the flow execution engine to diagnose slow or failing steps in production## **Offer details****Location**: Paris hybrid (\~3 days/week) or remote within France**Contract**: Full-time / CDI**Salary**: €60K–€90K gross + top of market for level + 20% bonus on collective milestones

Skills

• PostgreSQL
• Rust
• TypeScript
• Distributed Systems
• Docker