Top Software Engineer Jobs in St. Louis, MO

Build and maintain scalable microservices, APIs, and responsive React/TypeScript UIs for a modular security-operations platform. Integrate sensors and devices, implement real-time features (WebSockets, Kafka), design data models, participate in CI/CD, code reviews, sprint planning, and optimize full-stack features in a DevOps environment.

Leads technical architecture and roadmap for Mattermost’s core web platform across Go, React, and TypeScript. Owns distributed systems, API design, testing strategy, internal engineering tooling, security and compliance alignment, and quality standards. Mentors senior engineers, influences multiple teams, drives AI-agentic development practices, and contributes to the open-source codebase.

Own and manage client relationships, make architectural decisions, run discovery and stakeholder interviews, deliver software or automations, and contribute intellectual property back to the practice.

Design, develop, deploy, and support complex OneStream software features and services. Own end-to-end delivery, APIs, SDKs, data contracts, performance, scalability, reliability, and production quality. Lead technical design discussions and code reviews, mentor engineers, improve CI/CD and testing practices, and collaborate cross-functionally. Build user interfaces with modern frameworks, resolve production issues, and responsibly use AI-assisted development tools while ensuring correctness, security, and architectural alignment.

Develop, test, and maintain enterprise software components across the full software development lifecycle. Build user interfaces, REST APIs, services, and data access logic using Microsoft technologies and modern UI frameworks. Write unit tests, participate in code reviews, debug defects, and collaborate with Product, QA, and senior engineers. Use AI-assisted development tools while validating output for correctness, security, and architectural alignment.

Design, architect, develop, and maintain OneStream Marketplace solutions using web, cloud, SQL, and enterprise platform technologies. Lead design and code reviews, define APIs and coding standards, optimize application and database performance, support deployment automation, and ensure software quality. Mentor engineers, train new hires, guide requirements discussions, approve pull requests, and collaborate with technical and non-technical stakeholders to deliver customer-focused solutions.

Evaluate AI coding-agent interactions for usefulness, correctness, engineering judgment, explanation quality, and user trust. Provide rigorous, opinionated feedback distinguishing response quality levels and help define best practices for tools such as OpenAI Codex, Claude Code, and Cursor. This contract role requires experienced software engineering judgment rather than production coding.

Evaluate AI coding-agent interactions for usefulness, correctness, engineering judgment, reasoning quality, and developer trust. Provide clear, opinionated feedback, distinguish response-quality levels, and help define standards for excellent interactions with tools such as OpenAI Codex, Claude Code, and Cursor. This contract role requires staff- or principal-level software engineering experience and familiarity with modern AI-assisted development workflows.

Evaluate AI coding-agent interactions for usefulness, correctness, engineering judgment, reasoning quality, and user trust. Provide rigorous, opinionated feedback distinguishing response quality levels and help define best practices for tools such as OpenAI Codex, Claude Code, and Cursor. This contract role requires strong software engineering expertise, familiarity with AI-assisted development workflows, and the ability to assess code and explanations without deeply reviewing or executing every line.

Build and operate accessible, high-performance member-facing web applications using a front-end-first full-stack approach. Contribute to APIs, backend services, data flows, integrations, frontend architecture, testing, observability, and performance improvements. Own projects from concept through production, collaborate with Product, Design, Data, and Clinical teams, improve developer experience, support AI-assisted coding practices, participate in technical reviews and incident follow-up, and mentor engineers.

Build and deploy backend services, internal web applications, and tooling for item creation, enrichment, listing, configuration, and merchandising. Own features end to end, influence architecture, review code, improve reliability and observability, and collaborate with product, design, engineering, and business stakeholders. The role involves JVM and web technologies, event-driven systems, databases, GraphQL, production operations, and complex marketplace data.

Design, build, and maintain backend services and APIs using Ruby on Rails. Improve performance, scalability, reliability, and write well-tested production code. Collaborate with Product, Frontend, Data Engineering, and QA teams.

Design, build, and maintain backend services and APIs using Ruby on Rails. Ensure performance, scalability, reliability, and test coverage. Collaborate with Product, Frontend, Data Engineering, and QA to deliver production-quality code for web and mobile platforms.

Lead customers in observability strategy, telemetry schema design, sampling, instrumentation, and SRE practices. Build and ship production instrumentation, SLOs, and dashboards; mentor engineering teams; troubleshoot technical and sociotechnical issues; create enablement content; and represent customer insights internally. The role combines long-term technical advisory work with hands-on delivery across cloud platforms, infrastructure, CI/CD, and distributed systems.

Lead and architect scalable web systems, mentor frontend and backend developers, define coding standards and roadmaps, drive implementations using React/Next/Node/NestJS, produce technical documentation, conduct code reviews, and collaborate with product and DevOps to deliver secure, maintainable solutions.

Build, test, and optimize responsive web applications using Next.js and React. Collaborate with designers and back-end developers, implement UI/UX designs, write clean maintainable code, and debug front-end issues to ensure high performance across devices and browsers.

Lead and grow the front-end team while hands-on building high-performance web interfaces with React and Next.js. Define architecture, establish UI standards, conduct code reviews, mentor engineers, and collaborate with product, backend, and design teams to deliver scalable, accessible, and maintainable web applications.