Top Senior Software Engineer Jobs in St. Louis, MO

Designs and implements Go-based control-plane software for custom AI inference hardware. Responsibilities span system management APIs, Linux services, hardware interfaces, diagnostics, observability, security, firmware updates, distributed systems, and workload management. The role requires hands-on debugging across application, operating system, firmware, and hardware boundaries, plus technical leadership, mentoring, architecture, and production ownership. Regular on-site lab work includes server racking, system bring-up, hardware troubleshooting, and documentation.

Join as an early founding full-stack engineer to architect, build, and deploy a scalable platform serving AI-driven voice applications. You will own frontend and backend development, design infrastructure with the CTO, and deliver reliable production systems for enterprise customers.

Design, build, deploy, and maintain full-stack applications spanning frontend interfaces, backend services, APIs, databases, integrations, and cloud infrastructure. Own complex systems, improve reliability and technical debt, make architectural decisions, mentor engineers, and contribute to code reviews and engineering practices. Evaluate AI-assisted development opportunities and collaborate with product teams, stakeholders, and customers to deliver secure, maintainable software capabilities.

Develop scalable software and agentic workflow features for the AI Platform team. Build and maintain REST APIs, web interfaces, automation tools, and cloud-based applications; improve code quality through testing, reviews, refactoring, and secure engineering practices. Collaborate with architecture, security, DevOps, and infrastructure teams, while mentoring engineers and supporting continuous improvement.

Architect and deliver complex distributed systems using Azure cloud-native technologies, microservices, APIs, and event-driven patterns. Lead architecture reviews, reliability initiatives, performance optimization, incident response, and root-cause analysis. Drive adoption of AI-assisted development tools while maintaining security and code quality. Collaborate across engineering, DevOps, QA, and product teams, and mentor engineers on technical design, development practices, and AI-enabled workflows.

Build Apollo’s AI-powered Builder Studio end to end, including chat-driven app creation, live previews, generated-app runtimes, workflows, integrations, delegated permissions, security, and reliability. The role requires strong full-stack development, production LLM experience, frontend expertise with complex UIs, backend and workflow design, and ownership of an ambiguous 0-to-1 product.

Design, develop, debug, and improve Elastic’s cloud control-plane offerings. The role involves guiding cross-team architecture, leading development best practices, creating technical plans, diagnosing complex failures, prioritizing fixes and features, and collaborating with Support and Elasticsearch engineering teams. The engineer will contribute to reliable, scalable SaaS foundations while providing pragmatic technical leadership across a distributed engineering organization.

Design, build, operate, and maintain highly available distributed telemetry systems for Grafana Cloud and open-source projects. Deliver features end to end, improve reliability and performance, review code and designs, manage releases, participate in follow-the-sun on-call rotations, and collaborate remotely with teammates and customers. Work primarily with Go across Kubernetes-based cloud infrastructure and observability systems such as Mimir, Loki, Tempo, and Pyroscope.

Leads performance engineering across the organization by designing load-testing and data-generation frameworks, defining benchmarks and standards, analyzing application, database, and system behavior, and guiding teams in performance optimization. Builds reusable tooling and best practices using k6, JavaScript, Grafana, and InfluxDB while addressing scalability, latency, throughput, and reliability challenges in distributed cloud-native systems.

Develop and maintain Intelerad’s Unified Storage Layer and cloud storage services for medical imaging applications. Responsibilities include designing software features, translating support and stakeholder requirements into solutions, debugging cloud infrastructure, managing Kubernetes, Terraform, AWS, and CI/CD environments, reviewing code, documenting systems, and delivering work within an Agile/Scrum team.

Build and maintain authentication and fine-grained authorization systems using Auth0 and OpenFGA. Own OAuth 2.0 and OpenID Connect implementations, identity federation, token flows, and permissions for AI agents. Lead cross-team technical projects, set engineering standards, review code, and mentor engineers. The role requires strong backend development skills and experience with identity providers, ReBAC systems, and complex multi-tenant authorization models.

Build and own OpenRouter’s financial infrastructure, including flexible pricing, quote-to-cash automation, usage metering, billing, payments, collections, double-entry ledgering, provider settlements, and reconciliation. Ensure financial correctness through idempotency, auditability, anomaly detection, and access controls. Partner with Provider, Trust & Safety, Sales, Customer Success, and Finance teams to deliver scalable usage-based financial systems.

Develop and scale backend Java and Kotlin software powering patch discovery, packaging, and deployment across millions of endpoints. Design scalable systems, APIs, data structures, caching solutions, and relational databases while maintaining high testing and code-quality standards. Collaborate with AI workflow, server, platform, design, and product teams. Occasional React or Angular work may support patching workflows and dashboards.

Designs and evolves AWS infrastructure as code using CDK, develops backend software primarily in TypeScript, and applies secure engineering practices for regulated environments. The role contributes to architecture, code reviews, CI/CD pipelines, production support, observability, and on-call operations. It collaborates cross-functionally, builds scalable and reusable systems, supports SOC 2 compliance, and uses AI coding assistants to improve development, testing, and documentation.

Develop, test, and maintain mission-planning weapon software within a SAFe Agile scrum team. Translate requirements into designs, implement and integrate microservices (C#/C++ back end, JavaScript/TypeScript/React front end), debug issues, write documentation, and perform unit/integration/system-level testing and validation.

Own and deliver complex full-stack software features for custom labs and related applications. Design, build, test, document, and maintain APIs, databases, user interfaces, infrastructure, and libraries using C# or JavaScript/TypeScript. Lead AI-assisted development workflows, review generated code, ensure security and quality, collaborate with cross-functional Scrum teams, estimate scope, and participate in on-call support.

Design, develop, and modernize scalable front-end UI applications using Angular and TypeScript. Lead large UI projects, enforce coding standards, write technical specifications, optimize performance, mentor engineers, collaborate full-stack, and support CI/CD and Agile practices to deliver user-centric features.

Build and operate production Web3 products across backend, frontend, and smart contracts. Develop Go and TypeScript services, React dApps, SDKs, tokenization infrastructure, smart-wallet integrations, and blockchain event processing. Own on-chain/off-chain architecture, security, testing, observability, deployments, and on-call operations. Review code and configure AI-assisted engineering tools for the repository.

Develop and maintain C#/.NET software for electric and gas distribution engineering tools. Implement features, fixes, integrations, tests, and CI/CD automation while configuring enterprise systems for customer needs. Collaborate in Scrum, participate in reviews, reduce technical debt, document processes, and mentor teammates. The role may involve GIS or Enterprise Asset Management integrations and requires strong software development experience in utility or energy infrastructure environments.

Build and own mobile SDKs for identity and fraud prevention products, focusing on Android development, device-level signal collection, authentication, and emerging agentic identity use cases. Partner with product and engineering leaders on architecture and roadmap decisions, improve observability and production resilience, mentor engineers, and drive technical initiatives across Twilio and Stytch.

Build and operate large-scale audio data pipelines for AI model training. The role involves discovering data sources, developing reliable data-processing systems, optimizing quality, throughput, and cost, and collaborating with AI scientists. The engineer will own projects from discovery through implementation and ongoing improvement, using strong backend engineering skills in Python, Bash, and Linux environments.

Build and operate large-scale audio data pipelines for AI model training. Responsibilities include discovering data sources, improving data-processing systems for quality, throughput, and cost, collaborating with AI scientists, and owning engineering projects from discovery through continuous improvement. The role requires strong backend software engineering skills, production systems experience, and proficiency in Python, Bash, and Linux, with preferred experience in web crawling, distributed processing, GCP, Terraform, and audio or ML training data.

Build large-scale data pipelines and processing systems that produce high-quality audio datasets for AI model training. Discover data sources, optimize throughput, quality, and cost, operate production systems, and collaborate with AI scientists on next-generation models. The role requires strong backend software engineering, independent problem-solving, and ownership of projects from discovery through continuous improvement.

Build and operate large-scale data pipelines that collect audio data for AI training. Responsibilities include discovering data sources, optimizing data-processing systems for quality, throughput, and cost, collaborating with AI scientists, and owning engineering projects from discovery through continuous improvement.

Build and operate large-scale audio data pipelines for AI model training. Responsibilities include discovering data sources, developing reliable data-processing systems, optimizing data quality, throughput, and cost, collaborating with AI scientists, and owning engineering projects from discovery through continuous improvement.