Top Tech Jobs & Startup Jobs in London

Designs and operates cloud-native platform services, distributed systems, and large-scale compute, storage, and networking infrastructure supporting research, AI, and data-intensive workloads. Builds APIs, abstractions, automation, and deployment systems to simplify cloud resource management. Improves observability, performance, resiliency, and operational excellence while collaborating with researchers and engineers to deliver scalable production platforms.

Design, build, and operate high-performance Kdb+/Q platforms for real-time and historical market data, partnering with traders and researchers to deliver scalable time-series analytics, streaming, and trading solutions while driving architecture, automation, and operational excellence.

Leads EMEA People Operations across onboarding, employee changes, mobility, payroll inputs, benefits, records, and offboarding. Oversees regulatory compliance, HR data integrity, audits, reporting, vendor performance, employee queries, and process improvements across multiple European and Middle Eastern locations. Partners with HR, recruitment, compensation, benefits, legal, finance, IT, payroll, and external providers while supporting relocations, remuneration requirements, and HR-related expansion projects.

Lead architecture and engineering of high-performance crypto market feed handlers and exchange connectivity. Build low-latency ingestion, normalization, sequencing, order book construction, and distribution systems; drive venue onboarding, data quality, reconciliation, recovery, and replay; improve latency, throughput, resiliency in a 24/7 production environment; partner with trading and research teams; mentor engineers and define operational KPIs.

The role involves building and supporting production-level trading systems in C++ for credit and rates products, collaborating with traders and quantitative researchers.

Build full-stack, low-latency trading and pricing tools for options traders. Collaborate with traders, researchers, and business stakeholders to design intuitive frontends and scalable backend services, prototype and productionize distributed systems, and expand trading capabilities globally while improving performance, stability, and usability.

Build and optimize low-latency, high-performance C++ trading systems for crypto markets; partner with researchers and traders to productionize strategies; optimize latency, throughput, reliability; implement pricing, risk, and execution logic; analyze large-scale market and trade data; ensure resilience, testing, and scalability across global venues.

Conduct end-to-end ML research for options trading: design experiments, train large-scale models (LLMs/transformers), build scalable pipelines, validate and deploy models to production, and translate research into measurable P&L impact.

Software Engineers at Citadel develop, maintain, and support high-performance trading platforms, focusing on custom software solutions and system stability.

Design and develop software solutions, analyze complex problems, and provide support for trading activities in a dynamic environment.