Top Software Engineer Jobs in St. Louis, MO

Senior contractor engineer will own and evolve Thrive's enterprise platform end-to-end, starting on the Coaching app. Responsibilities include sustaining engineering (reliability, scalability, technical debt), delivering medium-to-large projects, partnering with Product and stakeholders, supporting on-call and incident response during US hours, and shipping high-quality, enterprise-facing features iteratively.

Lead the technical direction for the engineering team, architect systems, design APIs, and mentor engineers while improving backend infrastructure.

Lead technical direction and contribute to the frontend codebase, building user-facing tools and mentoring team engineers to enhance user experiences.

As a Staff Software Engineer, you'll develop and maintain core platform infrastructure, design scalable systems, mentor junior engineers, and ensure reliability of product features.

Lead technical strategy and execution for enterprise software, design and build new systems, improve existing platforms, mentor engineers, collaborate with product and stakeholders, ensure quality/performance, share best practices, analyze costs, and support operational readiness including on-call production support.

Design, develop, and maintain scalable full-stack web applications. Build reusable UI components, develop backend services and APIs, contribute to architecture, participate in code reviews, mentor peers, collaborate cross-functionally, and reduce technical debt while ensuring high performance and maintainability.

The Staff Software Engineer will lead projects, mentor team members, write code using Python, Django, React, JavaScript, and TypeScript, and impact the healthcare system with software solutions.

As a Senior Software Engineer at Medallion, you'll lead projects, mentor team members, and work with technologies like Python, Django, React, and TypeScript to impact healthcare operations.

Design and build core LLM platform primitives, safety and observability infrastructure, provider abstraction and evaluation systems, prompt lifecycle and Agent-as-a-Service; collaborate with product teams, document reference implementations, and lead technical standards to enable other engineers to build production AI features.

The Staff GenAI Backend Engineer leads engineering for intelligent routing systems, collaborates with teams to enhance customer support, and maintains architectural integrity in a high-availability environment.

Design and scale distributed systems for Ditto's edge-to-cloud capabilities, lead services development in Rust, and mentor engineers.

Build and own a framework-agnostic charting engine core and its React binding: rendering layers, real-time data plumbing, indicator math, drawing tools, performance (60fps) discipline, visual testing, architectural leadership, mentoring, and integrations across web and mobile.

Lead architecture and evolution of Juniper Square’s distributed services, cloud infrastructure, and developer platform. Design scalable, multi-tenant, event-driven systems; build paved-road developer tooling, CI/CD, and observability. Hands-on coding, prototyping, and performance troubleshooting. Enable production AI/LLM workloads, ensure security/compliance, support enterprise upmarket needs, and mentor engineering teams to raise operational excellence and reliability.

As a Senior Software Engineer, you'll design and maintain frontend applications and reusable components, integrate APIs, mentor engineers, and ensure high-quality user experiences in the fintech space.

As a Senior Software Engineer at Flex, you'll design and maintain financial services architecture, mentor junior engineers, and ensure scalability and security for innovative financial products.

Design, develop, and administer databases and web applications for IVR and call center software. Build cloud-based integrations, write and maintain SQL, and participate in call center analytics system development and integration.

Design, build, and operate full‑stack features and platforms for Horizon. Work across frontend, backend, infrastructure, data, and developer tooling; formulate solutions, ship production code, improve reliability and developer productivity, and expand AI/agent-assisted workflows. Collaborate with product, customers, and cross-functional teams, review code (including agent-generated), and improve internal tooling, observability, and deployment workflows.

The Senior Software Engineer will architect and optimize AI-powered developer tools, enhance the SDLC, collaborate across teams, and mentor peers to improve engineering productivity.

Build and improve the end-to-end experience for new customers by implementing features across Python services, a GraphQL gateway, Auth0-based auth, and Terraform-managed GCP infrastructure. Collaborate cross-functionally to redesign discovery, evaluation, onboarding, and time-to-value while ensuring reliability, testing, and stable deployments.

Lead technical strategy and architecture across engineering, advise executives, de-risk early-stage ideas, and drive delivery of scalable web and mobile products. Mentor senior engineers, promote cross-team collaboration and AI adoption, partner with product and clinical stakeholders, participate in on-call rotation, and ensure systems meet standards for stability, maintainability, and scalability.

Lead design, development, and maintenance of cloud hosting management and orchestration solutions. Mentor engineers, review code for quality and security, design REST APIs, troubleshoot issues, improve performance and reliability, and drive requirements and architecture decisions to enhance customer experience.

Lead backend development using C#/.NET and cloud-native technologies. Build and maintain APIs, ensure quality and performance, troubleshoot issues, conduct code reviews, and drive software/process improvements.

Build and operate backend systems enabling enterprise deployments of Coder. Design and implement scalable backend architecture, improve upgrade and migration reliability, investigate and resolve production scalability issues, own operator-facing backend features, document tradeoffs, participate in design reviews and on-call rotations.

Lead design, implementation, and operation of production-quality DevOps platforms and automated test infrastructure for heterogeneous edge hardware. Improve CI/CD, build/release, deployment automation, developer tooling, and platform reliability. Enable reproducible tests, diagnose failures across devices, partner with engineering and QA, and drive major infrastructure initiatives from ambiguity to production.

Design, build, and own the Fastpath Assure connector for NetSuite (primary) and Oracle EBS/Cloud. Develop SuiteScript, saved searches, data extraction logic, and PL/SQL integration components. Drive roadmap, troubleshoot customer environments, collaborate with product and engineering, mentor engineers, and contribute customer-facing content and webinars.