What the role involves
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
What they ask for
About Windmill
Windmill is an open-source developer platform that turns scripts into workflows, internal tools, and full-stack apps. Write scripts in Python, TypeScript, Go, Bash, Rust, SQL - Windmill auto-generates UIs from their parameters, handles dependencies, credentials, permissions, and scheduling so you focus on business logic, not infra. Open-source alternative to Airflow, Temporal, Retool and n8n. Chain scripts into flows with branching, parallelism, retries. Build dashboards with the app builder. Trigger via cron, webhook, or UI. All-in-one runtime, editor, secret manager, and OAuth platform - enterprise-ready out of the box. Stack: Rust / TypeScript + Svelte / PostgreSQL. Self-hostable, easy to deploy, built for performance and DX.
Full Windmill profile