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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Trading Systems Engineer - **Company:** Bluewalker Capital - **Location:** Barcelona, Spain - **Contract:** Permanent contract - **Skills:** Application Programming Interfaces (APIs), Artificial Intelligence, Relational Databases, Linux, DevOps, Python (Programming Language), Key Management, PostgreSQL, Message Passing Interface, Redis, Data Logging, Large Language Models, Concurrency, State Machines, Indexer, Information Technology, Docker - **Published:** August 17, 2026 - **Apply:** https://www.jobleads.com/es/job/ed345aa7c1435cd22a7b99a197ac04ad8 ## About the Role * 2+ years of hands-on production experience in Python, including asyncio, WebSocket clients, and event-loop behaviour under sustained load. * Production experience in Rust, with demonstrated work. Ownership, borrowing, lifetimes, traits, and generics. * Async Rust: Tokio, Send/Sync bounds, cancellation safety, and the effect of blocking work on an async runtime. * Concurrency: message passing versus shared state, channel and lock selection, atomics and memory ordering. * Experience with systems where state correctness is a primary requirement: idempotency, retry semantics, and reconciliation against an external source of truth. * Relational databases and in-memory stores (Postgres, Redis, or equivalent): schema design, indexing, and transactional boundaries. * Working knowledge of OpSec practices, secrets management, in both personal workstation and production environments. * Docker and Docker Compose, and the DevOps needed to provision servers, run and supervise long-lived services, configure networking, and work in Linux. * Ability to design and write production-grade systems without LLMs, while being proficient and deeply integrated with AI tools to maximize development velocity. * A background in statistics, computer science, mathematics, physics, or other quantitative fields. Soft Skills * Self-starter with intense intellectual curiosity. * Preference for diagnosing a live system over deploying a speculative fix. * Comfort working on code you did not write and cannot fully rewrite. ## Description We are a small engineering team, which means your responsibilities scale rapidly and your impact is clear and foundational. You would own the execution path end to end: order submission, fill handling, position tracking, reconciliation, and the risk controls around them. The stack spans two languages. Python covers services where iteration speed matters most; Rust covers latency-critical and concurrency-heavy components., * Own the order execution path: submission, fills, cancellations, retries, and the state machine tracking order lifecycle. * Build and maintain risk controls: exposure limits, drawdown monitoring, kill switches, and their alerting. * Profile and optimise latency-sensitive paths, with measurements before and after. * Make forward-looking architectural decisions, balancing risk, performance, cost, and maintainability. We offer flexibility, not hand-holding. * Stress-test and strengthen critical systems for robustness and clarity. A dependable existing feature set matters more to us than new features. * Extend the platform to new venues and instruments as our research grows., * Prior integration with exchange or broker APIs, and experience with order management or execution systems. * Market microstructure: order books, fee structures, slippage, and execution quality measurement. * Performance measurement with flamegraphs, perf, criterion, and latency histograms, reported at p99 and p99.9. * Lock-free structures: SPSC/MPSC ring buffers, bounded queues, and cache-line and false-sharing effects. * Thread-per-core or shared-nothing designs, and core pinning. * Property-based and deterministic testing of concurrent code: proptest, loom, fuzzing, or replay against recorded feeds. * Rust-Python interop via PyO3 or FFI. * Observability: metrics, structured logging, and tracing. * Experience inheriting and hardening systems you did not write. ## Related Videos - [Docker network without Docker](https://www.wearedevelopers.com/videos/1418-docker-network-without-docker) - [Reducing LLM Calls with Vector Search Patterns - Raphael De Lio (Redis)](https://www.wearedevelopers.com/videos/1714-reducing-llm-calls-with-vector-search-patterns-raphael-de-lio-redis) - [Docker Compose: Rediscovered](https://www.wearedevelopers.com/videos/1978-docker-compose-rediscovered) - [Inside Bitpanda's Tech Stack: Scaling a European Fintech Leader - Markus Dorner](https://www.wearedevelopers.com/videos/1979-inside-bitpanda-s-tech-stack-scaling-a-european-fintech-leader-markus-dorner) - [Docker exec without Docker](https://www.wearedevelopers.com/videos/1094-docker-exec-without-docker) - [Docker build without Docker](https://www.wearedevelopers.com/videos/100114-docker-build-without-docker) ## Related Articles - [How We Built a Worry-Free System That Runs for 10+ Years – And What We’d Do Again](https://www.wearedevelopers.com/magazine/751-how-we-built-a-worry-free-system-that-runs-for-10-years-and-what-we-d-do-again) - [Building AI Solutions with Rust and Docker](https://www.wearedevelopers.com/magazine/494-building-ai-solutions-with-rust-and-docker) - [Dev Digest 120 - Apple and peers](https://www.wearedevelopers.com/magazine/455-dev-digest-120-apple-and-peers) - [Dev Digest 137 - AI'm not sure about this](https://www.wearedevelopers.com/magazine/485-dev-digest-137-ai-m-not-sure-about-this) - [Dev Digest 131 - AI'm not sure about OSS](https://www.wearedevelopers.com/magazine/472-dev-digest-131-ai-m-not-sure-about-oss) - [Dev Digest 138 - Are you secure about this?](https://www.wearedevelopers.com/magazine/486-dev-digest-138-are-you-secure-about-this)