Senior Software Engineer; SMTS — Ultra Messaging

Role Overview

The Senior Software Engineer SMTS role is part of the Ultra Messaging (UM) team, a small, specialized group of engineers building and maintaining one of the industry's most demanding real-time messaging middleware platforms. Ultra Messaging is mission‑critical infrastructure for some of the world's largest financial institutions — including major global banks, trading firms, market makers, and exchanges — where microseconds matter and reliability is non‑negotiable.

The team works remotely with a preference for candidates in the Chicago area, where several team members are based. You'll be working on a mature, production‑grade, system‑level C codebase that has been powering real‑time financial data flows since 2004.

If you're a low‑level systems programmer who loves performance, concurrency, and working on software that has to work right, every time — this is your role.

• Analyze requirements for new features, enhancements, and bug fixes; produce clear requirements documents.
• Evaluate the existing codebase to determine optimal design approaches; produce design documents.
• Implement changes primarily in the core C layer, with occasional work in Java (via JNI) and .NET (C#) API wrappers for cross‑platform support.
• Write and execute development-level tests to validate correctness and performance.
• Collaborate with and support QA and customer support engineers throughout the development lifecycle.
• Occasionally engage directly with customers on technically complex issues when escalation is warranted.

• You have 5+ years of experience writing production-quality C or C++ code.
• You have hands‑on experience with multi‑threaded programming
  , including concurrency patterns and thread synchronization primitives.
• You understand performance optimization at the system level — you know how to find bottlenecks and eliminate them.
• You have strong debugging skills and are comfortable diving deep into complex, unfamiliar codebases.
• You have strong written communication skills — you'll be producing requirements and design documents, and occasionally working through complex technical issues directly with customers.

• You know Java — and bonus points if you've worked with JNI (Java Native Interface).
• You have experience with networking protocols
  , including UDP multicast.
• You've done socket programming at a low level.
• You've used performance profiling tools and have a methodology for systematic performance analysis.
• You have experience with messaging middleware — UM, Aeron, TIBCO EMS, Tibco RV, Kafka, or similar.