Jobs › Simplex Trading

Infrastructure Engineer

Simplex Trading · Chicago, IL · $125,000–$200,000 a year · Development

Posted Sep 11, 2026 · We last checked this listing on Oct 6, 2026

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Likely interview questions for this role

Written from this job description, not a generic list. Each one notes what the interviewer is really checking.

About your past

Tell me about a Linux issue you diagnosed at the kernel, module or filesystem level.

What they are checking: Real depth in Linux below the surface, which the posting specifically asks for.

You will occasionally work onsite at colocation facilities in Chicago, Aurora and New Jersey. What hands-on hardware work have you done?

What they are checking: Comfort with physical racking, cabling and replacing parts, not only remote administration.

Tell me about a change you made that caused an outage. What happened next?

What they are checking: Honesty about mistakes and whether they improved process afterward.

What would you do

How would you plan and execute a change to production servers that must happen outside trading hours?

What they are checking: Discipline around change windows, testing and rollback plans in an environment where downtime costs money.

An alert fires at market open saying a server's network latency doubled. Walk me through your triage.

What they are checking: Calm, ordered troubleshooting under time pressure when traders are waiting.

How do you decide when to fix something yourself and when to bring in the team?

What they are checking: Good judgment about working alone versus escalating, as the posting mentions both.

About the work

What monitoring would you set up for trading servers in a colocation facility?

What they are checking: Whether they know what to watch, like latency, clock sync, hardware health and network, and what to alert on.

How have you automated server deployment or configuration?

What they are checking: Experience with tools like Ansible or scripts that keep many machines consistent.

How would you tune a Linux system for low latency?

What they are checking: Familiarity with CPU isolation, interrupt handling, power settings and other tuning used in trading.

What networking knowledge do you rely on most in your day-to-day work?

What they are checking: Whether they understand enough networking to troubleshoot alongside systems work.

Practice this interview out loud.

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The full job description

As published by Simplex Trading.

Our employees are our greatest asset. We have spent years building a team of talented, dedicated technologists, data-driven traders, and expert leaders with an emphasis on our core pillars: People, Process, Trading Edge, and Technology. Simplex is an in-office organization, helping to foster a collaborative and communicative culture. Career Description Simplex is looking for smart, curious, and driven individuals to join our technology team. Technology at Simplex is the core of the business. We are a leading technology-driven proprietary market-making firm. You will be someone excited by challenges and proactive in problem-solving.  What will you be doing? • Develop and maintain monitoring and deployment systems (Systems and Network) • Triage and respond to issues • Prepare and execute changes to the Linux environment • Maintain and deploy servers and workstations • Projects will be completed both independently and as a part of a team, when necessary • This is an in-office position, with occasional onsite work at several colocation facilities in Chicago, Aurora, and New Jersey • Infrequent evening/weekend work to allow for change execution outside of trading hours • Other opportunities as assigned Skills and Experience: • 3+ years of experience as a System Administrator, Linux Administrator, or similar • Thorough understanding of Linux (kernel, modules, filesystems) with special emphasis on the network stack, especially multicast, and OpenOnload • Experience working with Linux and standard tools (bash, grep, sed, awk) and scripting languages (Python, Perl, bash) • Understanding of Linux concepts (kernel, modules, memory allocation, filesystems) • Familiarity with common server technologies (IPMI, SNMP), or software (Nagios, Ansible, dnf/rpm, git) • Experience troubleshooting complex performance issues • Ability to lift and move heavy equipment (40-50 lb regularly) Annual base salary ranges from $125,000 to $200,000, and is influenced by a number of factors, including qualifications and experience. This role is also eligible for an annual discretionary bonus, of which can be a significant portion of total compensation. This full time role is also eligible for other forms of compensation and benefits including health/dental/vision insurance, and 401(k) contributions.   Infrastructure Engineer pay range $125,000 — $200,000 USD Why us? Founded in Chicago in 2004, Simplex is a leading, technology-driven, proprietary market-making firm. We work with the most advanced technology and software in the market, and we’ve continued to remain at the forefront of the industry by always focusing on innovation, automation, and data-driven analysis. We also leverage our experience and expertise to make strategic investments and capitalize on opportunities in the venture capital markets with promising, early-stage financial and technology start-ups.  PLUS, the goods! • Benefits: Excellent a la carte Medical/Dental/Vision (free employee coverage!), 401(k) match, generous parental leave! • The Office: The kitchen is stocked with snacks, and beverages; you also have daily stipends for breakfast and lunch!  • Tuition Reimbursement: As an investment in our employees’ careers and the company’s future, we offer educational assistance to provide employees with professional development opportunities that increase their skills and enhance their contributions to the organization! • Employee Discounts: To gyms, national brands, and more! • Building:  We are located in the Federal Reserve building. As a tenant, you have access to a building gym and a full cafeteria. We are easily accessible to all public transportation. • Charity Match: We match up to $2,000 a year in donations to the charities of your choice! • Fun Events: In-person happy hours, celebrations throughout the year, game nights, video game fun, and so much more! Simplex is an Equal Opportunity Employer. Simplex and its recruitment partners may use artificial intelligence (AI) tools to support certain aspects of the recruiting and hiring process. Final hiring decisions are made by humans. For all job postings, Simplex may use AI to review and analyze applications, resumes, interviews, and applicant responses.  Simplex complies with applicable federal and state laws governing AI use. Applicants may still request reasonable accommodations. For more information related to AI or to request an accommodation, please contact  HR@simplextrading.com . 

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