Top Senior Software Engineer Jobs in St. Louis, MO

Design, build, and maintain Python-based systems that interface with custom hardware. Own hardware drivers across serial/USB/I2C/SPI/Modbus, implement maintainable state machines, write async event-driven code, build RESTful APIs, persist device telemetry in SQL, contribute computer vision work, and collaborate with hardware, firmware, and operations while mentoring engineers and raising engineering standards.

Design, build, and operate shared backend services and APIs. Own full SDLC, define service boundaries and data models, ensure scalability and reuse, apply DDD and systems thinking, and use AI-assisted tools to accelerate development while maintaining maintainability.

Build and ship lightweight internal full-stack tools end-to-end within small pods. Rapidly prototype, deploy, operate, and iterate tools using cloud platforms and AI-assisted development to improve team productivity and automate workflows.

Design, build, and ship full‑stack applications end-to-end within small pods. Own the full SDLC, deploy and operate cloud applications, contribute to architecture, and use AI-assisted tools to accelerate development, testing, and code quality while maintaining reliability.

Develop and maintain backend services for the Leap quantum-classical cloud platform. Deliver features across the SDLC, improve system performance and scalability, troubleshoot and resolve production issues, participate in code reviews and on-call rotation, mentor junior developers, and collaborate with cross-functional teams to ship reliable, high-quality software.

Lead design and development of software that interfaces with quantum processors, supporting calibration, hardware interfaces, testing, monitoring, and operational infrastructure. Drive architecture, optimize performance, mentor engineers, run technical investigations, and participate in on-call rotations to ensure QPU solver availability on the Leap cloud platform.

As a Senior Software Engineer at SmithRx, you will design, develop, and maintain back-end architecture for our product suite using various programming languages, collaborate with stakeholders, ensure high-quality software, and mentor junior team members.

Lead end-to-end design, implementation, and operation of cloud partner integrations: auth/identity flows, multi-tenancy, data movement, CI/deployment, and observability. Own production systems and on-call duties, collaborate with partner platforms and internal teams, write design docs, and set technical defaults for a growing team.

As a Senior Backend Engineer, you will enhance Postscript's Fondue product by architecting scalable systems, driving decoupling, and implementing AI-first development practices while collaborating across teams.

As a Principal Software Engineer at Fetch, you'll design scalable systems for user engagement, drive experimentation, lead technical strategy, and mentor teams to improve engineering productivity and system reliability.

The Sr./Principal Software Engineer will design and implement core capabilities for SingleStore's cloud platform, focusing on scalability and reliability, while mentoring other engineers and collaborating with cross-functional teams.

Design and develop scalable backend systems for SaaS applications, mentor engineers, and lead projects while collaborating with cross-functional teams.

The Staff Software Engineer will lead the software development lifecycle focusing on observability, design high-scale distributed systems, and mentor team members while ensuring technical excellence.

Design, build, and maintain backend systems and APIs for the Wikidata Query Service. Improve reliability, observability, automation, and scalability; monitor production, respond to incidents, support migrations, and collaborate across SRE, data, and product teams.

The Staff Software Development Engineer will lead and contribute to the development of CVS Health's digital platform, focus on customer-centric solutions, mentor junior developers, and ensure high-quality code delivery across projects.

The Senior Software Engineer will design and build scalable data solutions, manage backend systems, and enhance performance leveraging Golang and Python. Responsibilities include optimizing ETL processes and collaborating with teams to meet evolving customer needs.

The role includes leading a team of database engineers, designing and optimizing Oracle databases and AWS data services, and overseeing data migration efforts. Responsibilities involve collaboration across teams, performance tuning, and managing production support.

Principal IC responsible for reliability, observability, and modernization of a .NET-based Platform Services portfolio on Azure. Own architecture, resilience patterns, shared libraries, and migration of legacy .NET services. Implement observability, event-driven messaging, and AI-first engineering practices while mentoring engineers and partnering with architecture teams.

Design, build, and operate cloud infrastructure and internal developer tooling to scale a production SaaS platform. Improve performance, scalability, and security, integrate observability, build AI-assisted automation, support production debugging and incidents, and participate in on-call rotations while enabling strong developer experience and documentation.

Design, build, and operate high-throughput distributed data pipelines and platform infrastructure. Own end-to-end systems from architecture to production, write production-grade Python, optimize SQL at scale, architect service contracts, mentor engineers, and instrument systems for observability.

Lead design and hands-on development of AWS-based serverless backend and IoT cloud services. Build Python Lambda microservices, REST APIs, telemetry pipelines, and secure AWS IoT Core device communication. Mentor engineers, define architecture patterns, ensure production readiness (monitoring, CI/CD, security), and guide cross-functional integrations and technical roadmaps.

Own platform feature and API development, integrations, and deployments. Design, build, and maintain backend-focused full-stack features, collaborate with product and design, perform code reviews, troubleshoot, and work with cloud infrastructure and CI/CD pipelines to scale the marketplace.

Develop, deploy, and maintain the UDS Registry and related tools (Pepr, Lula). Lead architecture and implementation, integrate with defense systems, participate in on-call rotation, contribute to open source, produce documentation, mentor engineers, and influence product direction with user-focused design.

Lead design and implement scalable backend systems using Node.js, build RESTful APIs, design SQL schemas, optimize performance, mentor engineers, deploy on Azure, and maintain CI/CD, security, and observability.

Lead design and operation of the Synapse Everywhere external API platform: define API surface and guarantees, translate product and clinical requirements into contracts, own reliability and on-call incident response, provide technical mentorship and code reviews, and design scalable, secure cloud-native solutions (k8s, LLMs) with strong developer experience.