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Joaquin Bejar

@joaquinbejar

Senior Quant & Backend Engineer | Rust, C++, Go, Python | Trading, options and distributed systems | Fully remote from Madrid

Spain

Message

What I'm looking for

Fully remote from Madrid, Spain; no relocation. Prefer 1 to 10 people; open to 11 to 50. Senior quant, Rust/backend or infrastructure work in trading, options, execution, market making or distributed systems. Available immediately. Employment or contract, worldwide companies. Target: USD 150,000/year or USD 100/hour.

Quant engineering leader with 20+ years designing and operating production software for electronic markets and digital assets. Hands-on in Rust, C++, Go and Python.

I lead exchange engineering across matching and limit order books, option chains, real-time risk, liquidation and institutional RFQ services, including SBE streams and REST/WebSocket APIs. I have built execution, smart order routing, FIX connectivity, transaction cost analysis and Greeks-based risk controls across crypto and traditional markets. My infrastructure work includes Kubernetes, AWS, PostgreSQL, Redis and NATS/Kafka.

I created OrderBook-rs, OptionStratLib and market-maker-rs, open-source Rust projects for limit order books, options pricing, Greeks, simulations, market making, risk management and backtesting.

Based in Madrid, Spain. Available immediately. Seeking fully remote senior quant, Rust/backend or infrastructure roles with companies worldwide, ideally teams of 1 to 10 people. Compensation target: approximately USD 150,000/year or USD 100/hour for contracts.

Personal website: https://joaquinbejar.capitaldelta.co

GitHub: https://github.com/joaquinbejar

Telegram: https://telegram.me/joaquin_bejar

Experience

Work history, roles, and key accomplishments

Current

Head of Quant Engineering

Current

LayerV

Jan 2026 - Present (9 months)

Lead the quant engineering team building a hybrid exchange for compound options structures. Own architecture, delivery and engineering standards. Built the matching and limit order books, option chains, real-time risk, liquidation and RFQ services, plus SBE streaming, REST and WebSocket APIs.

Current

Senior Quant Developer

Current

Capital Delta

Apr 2025 - Present (1 year 6 months)

Built a systematic options platform spanning volatility surfaces, pricing, trade selection and a Rust/Go execution kernel. Developed smart routing, cross-venue arbitrage, exchange connectivity, transaction cost analysis and Greeks-based risk controls. Operated Kubernetes, Redis, PostgreSQL and AWS across a global colo mesh.

Senior Quantitative Software Engineer

Sphinx

Aug 2024 - Apr 2025 (8 months)

Built market-making and liquidity-routing infrastructure for an onchain perpetuals exchange, including dynamic quoting, delta-neutral hedging across futures, CEXs and AMMs, and margin and inventory controls. Developed a Rust/Go/Python stack with Kubernetes, Redis, PostgreSQL and AWS, plus telemetry and oracle sanity checks.

Senior Quantitative Developer

Swissblock

Nov 2022 - Aug 2024 (1 year 9 months)

Developed an algorithmic cryptocurrency trading platform, exchange connectivity, order management and execution. Built a Go smart order router across venues using FIX and REST/WebSocket APIs, adaptive rate limits, transaction cost analysis and routing comparisons. Worked with Go, Python, C++, Rust, Kubernetes, Kafka and NATS.

Senior Software Developer

BlackBird.video

Mar 2022 - Nov 2022 (8 months)

Moved complex applications to AWS microservices, ECS and Lambda. Built low-latency, high-throughput audio and video systems in C++, Rust, Python, Bash and Go, with CI/CD, Docker and Kubernetes.

Quant Developer

Flow Traders

Feb 2019 - Mar 2022 (3 years 1 month)

Designed and delivered smart order routing in modern C++ for multi-venue execution using FIX and native APIs. Built transaction cost analysis, routing comparisons, exchange connectivity and microsecond-level telemetry. Worked with C++, Python, REST, WebSocket, gRPC, FIX and SBE.

Senior Security Software Developer

EUIPO

Sep 2018 - Mar 2022 (3 years 6 months)

Led development of security services and data pipelines protecting web portals. Built APIs for GeoIP and Layer 7 attack analysis using Python, C++, Bash, MongoDB, Redis and MariaDB, with AWS, Azure, Docker, Kubernetes, Terraform and GitLab CI/CD.

Senior Software Developer

Joint Research Center

Jul 2017 - Sep 2018 (1 year 2 months)

Led development of an AI model to predict malaria outbreaks in countries with limited data. Worked with AWS, C++11, Python, Docker, GitLab, CI/CD and MySQL.

Software Developer, Taxes & Customs

European Commission

Nov 2016 - Jul 2017 (8 months)

Developed data analysis and predictive modelling applications for fraud detection in financial data using AWS, C++11, Python, Pandas, Scikit-Learn, Docker, Git and Hadoop.