New

C# Developer

TEKsystems
$80.00 - $100.00 / hr
life insurance, sick time, 401(k), retirement plan
United States, Illinois, Chicago
May 15, 2026
Senior Software Engineer - Capital Markets (C#/.NET) Location: Onsite (5 days/week) Type: Contract-to-Hire Level: Senior / Associate upon conversion Role Overview We are seeking a Senior Software Engineer to join a high-impact engineering team responsible for building and extending real-time, mission-critical systems supporting portfolio valuation, pricing, and execution workflows in the capital markets space. This role focuses heavily on backend development, data integration, and scalable, multi-threaded systems. You will work closely with technologists and business stakeholders to design, build, and enhance applications that ingest large volumes of external market data, perform complex calculations, and expose that data internally and externally with high reliability and performance. Core Responsibilities * Design, build, and maintain backend services using C#/.NET * Develop and optimize SQL Server data models and queries for large-scale datasets * Integrate data from multiple external sources (market data providers, third-party vendors) * Build and maintain multi-threaded applications to support complex, real-time calculations * Contribute to system scalability, performance tuning, and operational stability * Participate across the full SDLC: system design, development, testing, deployment, and support * Collaborate in an Agile environment with engineers, product, and business stakeholders Required Technical Skills * Advanced C# / .NET development experience (current environment on .NET Framework; future migration to .NET Core) * Strong backend engineering experience with SQL Server and native SQL * Experience handling large data sets and performance-sensitive systems * Proven expertise in multi-threading, concurrency, and thread safety * Experience building middle-tier services at scale * Hands-on experience integrating with external systems using REST, SOAP, FIX, or secure file transfer * Familiarity with real-time systems (non-batch, low-latency processing) Capital Markets Knowledge (Must Have) Strong understanding of how financial products trade and are valued, including: * Equities * Fixed Income (Bonds, Treasuries, Structured Products) * Derivatives (Options, Futures, Swaps - e.g., IRS, CDS, Equity Swaps) * Foreign Exchange (FX) * General knowledge of trading operations, portfolio management, and market structure * Ability to discuss concepts such as pricing, fair value, volatility, and risk metrics Nice-to-Have / Preferred Skills * Experience with Execution Management Systems (EMS) or Order Management Systems (OMS) * Exposure to Portfolio Management or valuation platforms * Knowledge of containerized applications and Kubernetes-based deployments * Familiarity with cloud-native development (GCP, AWS, or Azure) * Experience with messaging technologies (Kafka, RabbitMQ) * Experience with caching technologies (Redis, Hazelcast) * Basic exposure to modern UI frameworks (HTML, React) * Understanding of CI/CD, application resiliency, and security best practices Education * Bachelor's degree in Engineering, Computer Science, Mathematics, or a related technical field (or equivalent experience) Experience Level * 5+ years of professional software engineering experience * Demonstrated ability to build scalable, high-performance systems in complex domains Interview Process * Initial 30-minute introductory and background discussion * Technical panel interview Why This Role * Work on real-time, high-impact systems within capital markets * Opportunity to influence architecture and modernize legacy systems * Environment that values technical depth, ownership, and continuous learning Job Type & LocationThis is a Contract to Hire position based out of Chicago, IL. Pay and BenefitsThe pay range for this position is $80.00 - $100.00/hr. Eligibility requirements apply to some benefits and may depend on your job classification and length of employment. Benefits are subject to change and may be subject to specific elections, plan, or program terms. If eligible, the benefits available for this temporary role may include the following: * Medical, dental & vision * Critical Illness, Accident, and Hospital * 401(k) Retirement Plan - Pre-tax and Roth post-tax contributions available * Life Insurance (Voluntary Life & AD&D for the employee and dependents) * Short and long-term disability * Health Spending Account (HSA) * Transportation benefits * Employee Assistance Program * Time Off/Leave (PTO, Vacation or Sick Leave) Workplace TypeThis is a fully onsite position in Chicago,IL. Application DeadlineThis position is anticipated to close on May 20, 2026. About TEKsystems We're partners in transformation. We help clients activate ideas and solutions to take advantage of a new world of opportunity. We are a team of 80,000 strong, working with over 6,000 clients, including 80% of the Fortune 500, across North America, Europe and Asia. As an industry leader in Full-Stack Technology Services, Talent Services, and real-world application, we work with progressive leaders to drive change. That's the power of true partnership. TEKsystems is an Allegis Group company. The company is an equal opportunity employer and will consider all applications without regards to race, sex, age, color, religion, national origin, veteran status, disability, sexual orientation, gender identity, genetic information or any characteristic protected by law. About TEKsystems and TEKsystems Global Services We're a leading provider of business and technology services. We accelerate business transformation for our customers. Our expertise in strategy, design, execution and operations unlocks business value through a range of solutions. We're a team of 80,000 strong, working with over 6,000 customers, including 80% of the Fortune 500 across North America, Europe and Asia, who partner with us for our scale, full-stack capabilities and speed. We're strategic thinkers, hands-on collaborators, helping customers capitalize on change and master the momentum of technology. We're building tomorrow by delivering business outcomes and making positive impacts in our global communities. TEKsystems and TEKsystems Global Services are Allegis Group companies. Learn more at TEKsystems.com. The company is an equal opportunity employer and will consider all applications without regard to race, sex, age, color, religion, national origin, veteran status, disability, sexual orientation, gender identity, genetic information or any characteristic protected by law. San Francisco Fair Chance Ordinance: Pursuant to the San Francisco Fair Chance Ordinance, for all positions located in the city and county of San Francisco, we will consider for employment qualified applicants with arrest and conviction records. Massachusetts Lie Detector: It is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Use of Artificial Intelligence (AI): We may use Artificial Intelligence (AI) to support parts of our hiring process, including sourcing, screening, and evaluating candidates. AI helps assess applications and qualifications, but final decisions are made by our hiring team. By applying, you acknowledge and agree that your application may be reviewed using AI tools.