Warren (Ryn) Buhler

Software Engineer

London, England, United Kingdom

About

Experienced software engineer, project manager, and customer technical support specialist. Skilled in crisis management, product requirements elicitation, as well as communication to technical and non-technical audiences. Passionate about using technology to solve business challenges

Experience

  • Full Stack Engineer at Undisclosed
    Oct 2024 - Present · 1 yr 9 mos

  • Software Developer at Trayport
    Oct 2022 - Oct 2024 · 2 yrs 1 mo

    • Led implementation of new Self-Match Prevention (SMP) functionality for an electronic trading platform, preventing clients from unintentionally trading against their own orders • Refactored complex order translation workflows into scenario-specific processing paths, improving maintainability, reliability, and reasoning around order state transitions • Identified and documented a race condition in a third-party exchange implementation that could lead to overexposed trading positions during concurrent order updates • Designed and implemented asynchronous climate market data connectors under tight delivery timelines for an urgent release; subsequently mentored junior engineers and helped drive a reusable shared implementation that reduced development time for future connectors from weeks to days • Implemented end-to-end two-factor authentication (2FA) workflows for energy exchanges, including backend services, frontend administration tooling, rollout planning, and operational coordination • Key technologies: C#, SQL, RabbitMQ, Autofac, Moq

  • Server Systems Engineer, Team Lead at Epic
    Sep 2016 - Jul 2021 · 4 yrs 11 mos

    • Led a team of 10 part-time software engineers working on internal tools for the Systems teams, setting technical direction, prioritizing work, and reviewing implementations to ensure high-quality, timely delivery • Developed internal product to automatically detect hospital system outages based on workflow telemetry and operational metrics • Partnered with Security leadership to design a new incident-reporting workflow within the Epic community, dynamically tailoring guidance and response questions for engineers handling security events • Provided technical expertise on Electronic Medical Records (EMR) performance, uptime, and infrastructure reliability for major healthcare organizations including Kaiser Permanente, Johns Hopkins, and Novant Health, supporting systems serving over 15 million patients • Managed a team of four Server Systems Engineers through technical mentorship, performance reviews, and career development guidance • Advised hospitals on healthcare interoperability and infrastructure scaling, including data archival and retention strategies that reduced storage costs across terabytes of clinical data • Led the cross-functional Systems Health Escalation Group, coordinating responses to third-party infrastructure issues impacting hospital EMR systems • Responded to critical infrastructure outages during COVID-19 and presented infrastructure capacity and reliability findings to all Systems teams

  • Markets and Securities Services Intern at Citi
    Jun 2015 - Sep 2015 · 4 mos

    • Learned fundamentals of equity options trading and agency lending while working on trading floor • Developed new VBA program to monitor liquidity in listed options, highlight areas of interest, and provide tools to traders for further analysis; worked with IT to automate daily distribution • Analyzed pricing for a proposed new service for brokers; prepared presentation for senior management; prepared Product Update Notes to inform beneficial owners about Citi’s Agency Lending Services

  • Market Analyst at ScentAir
    May 2014 - Jun 2014 · 2 mos

    • Researched historical trends and calculated growth projections for key East Asian retail industry segments • Identified consumer market leaders and key executives to inform customer acquisition strategy