Top Senior Software Engineer Jobs in St. Louis, MO

Provides principal-level technical leadership across engineering teams, shaping architecture, engineering standards, scalable software solutions, and delivery practices. The role combines hands-on software development with design reviews, technical decision-making, mentoring, CI/CD and platform improvements, system reliability, and cross-team collaboration. It also partners with product and design stakeholders and may lead high-impact initiatives. Remote work is available with required quarterly travel to Tampa, Florida.

Owns end-to-end test strategy, designs scalable backend and UI automation frameworks, integrates automated testing into CI/CD pipelines, performs exploratory testing, and advocates for testability and reliability across engineering and product. The role requires strong programming, Kubernetes and distributed-systems knowledge, debugging ability, and cross-functional ownership in a fast-moving startup.

Lead technical direction for a central infrastructure team supporting all product engineering. Design and maintain AWS infrastructure, Terraform modules, CI/CD workflows, observability, security, networking, cost-visibility tooling, and operational platforms. Coordinate multiple initiatives, improve reliability and incident response, establish paved roads adopted by feature teams, guide infrastructure strategy, and coach engineers across the organization.

Build and optimize distributed Lance dataset operations, high-performance indices, table formats, and data encodings in Rust. Develop integrations with Spark, Hive Metastore, Presto, Trino, Ray, and other data infrastructure systems. Improve internal data processing infrastructure, contribute to open-source communities, and promote Lance through technical conferences. The role requires deep distributed systems expertise and extensive experience with high-performance databases, big data, or AI training systems.

Build and maintain premium mobile features, subscription and in-app purchase flows, paywalls, pricing experiences, and advertising functionality for Life360’s consumer app. Own feature quality, performance, reliability, experimentation, and incident response at 100M+ user scale. Collaborate with product, design, data science, and analytics teams; use AI coding agents extensively; contribute to architecture and code reviews; mentor engineers; and help evolve AI-native engineering practices.

Own end-to-end verification and validation for complex cloud-native software systems. Design comprehensive testing strategies, build scalable backend and frontend automation frameworks, identify coverage gaps, perform root cause analysis, integrate tests into CI/CD pipelines, and improve testing efficiency. Apply AI-assisted tools to testing and debugging, evaluate emerging AI capabilities, mentor engineers, and raise quality standards across teams.

Evaluates AI coding-agent interactions for technical quality, engineering judgment, reasoning, explanations, and user trust. Provides detailed written and recorded feedback, distinguishes response quality levels, and helps define standards for tools such as Codex, Claude Code, and Cursor. This remote contract requires strong TypeScript, JavaScript, or Python experience, familiarity with AI-assisted development workflows, and senior-level engineering judgment.

Evaluate AI coding agents such as Codex, Claude Code, and Cursor for engineering judgment, response quality, reasoning, explanations, and usefulness. Provide clear written and recorded feedback, distinguish quality levels, and help define standards for excellent AI-assisted development interactions. This contract role requires senior-level software engineering experience, strong Python or TypeScript/JavaScript skills, familiarity with modern AI development workflows, and excellent English communication.

Evaluate AI coding-agent interactions for correctness, usefulness, engineering judgment, explanation quality, and user trust. Provide clear, opinionated written feedback, distinguish response-quality levels, and help define standards for tools such as OpenAI Codex, Claude Code, and Cursor. The role requires senior-level software engineering experience, strong TypeScript/JavaScript or Python skills, hands-on AI-assisted development experience, excellent English communication, and the ability to assess code without executing or reviewing every line.

Build and operate full-stack certificate management, security, monitoring, and vulnerability products. Develop TypeScript APIs and React frontends, design MySQL schemas, manage AWS workers and Kubernetes infrastructure, maintain legacy .NET and Python services, integrate partner APIs, improve CI/CD and observability, participate in on-call support, and develop AI-assisted features. The role includes code reviews, testing, incident resolution, technical documentation, and mentoring engineers.

Design and scale Cohere’s Model Vault backend and inference platform. Lead architecture for authentication, deployments, billing, metering, customer lifecycle, and cloud control-plane services. Build reliable distributed systems with strong guarantees for security, privacy, consistency, isolation, observability, and failure recovery. Drive technically complex initiatives from threat modeling and architecture through implementation, production rollout, operations, and iteration at enterprise scale.

Develop and support software applications, REST and ASP.NET web services, distributed systems, data integrations, and storage solutions. Analyze requirements, optimize performance, resolve application issues, implement security and data protection, and collaborate with product, business, and QA teams. The role includes technical documentation, quality reviews, managing competing priorities, and mentoring less experienced developers.

Modernize and develop a large-scale React Native mobile application with reliable offline-first functionality, local data storage, synchronization, BLE device integrations, scalability, and strong performance. The role includes shaping architecture, improving engineering practices, collaborating cross-functionally, mentoring developers, providing technical leadership, and visiting customer farms to understand workflows. Requires extensive mobile development experience and occasional U.S. travel.

Build and maintain full-stack software for startup clients, including backend services, frontend experiences, new features, redesigns, bug fixes, and product improvements. Collaborate daily with product managers, designers, and engineers in a distributed, agile environment. Take ownership across the technology stack, write clean maintainable code, contribute to client missions, and support team growth and knowledge sharing.

Design, build, and operate scalable backend services and APIs. Develop integrations, shared data APIs, metrics storage, ETL pipelines, and AI-enabled product features. Diagnose reliability and performance issues, improve developer experience, and advance engineering practices. Collaborate with engineers, clients, and non-technical stakeholders while working effectively in a fast-changing startup environment.

Design and implement scalable backend services for MoneyGram’s core transaction and API platforms. Responsibilities include architecture, microservices, APIs, event-driven systems, integrations, cloud development, CI/CD automation, testing, deployment, operational excellence, and engineering standards. The role collaborates with product, engineering, and QA teams, mentors junior engineers, leads complex technical solutions, and influences technical direction in an agile environment.

Lead technical direction for Elastic’s billing experience platform. Design and evolve public and internal APIs, build full-stack billing and account-management features, and shape scalable architecture and data models. Improve reliability, observability, deployment, CI/CD, and incident response across cloud services. Mentor engineers, review technical work, influence roadmap priorities, collaborate across Product, Design, SRE, Finance, and Cloud teams, and participate in on-call rotations.

Design and scale ARM64 compute platform infrastructure, hypervisor integrations, instance management, resource orchestration tools, and compute APIs. Develop and maintain low-level services using Python, Go, or compiled systems languages. Collaborate with hardware and global engineering teams, participate in design reviews, debug distributed Linux systems, and mentor junior engineers.

The Senior Software Engineer will design and develop backend systems and APIs, mentor other engineers, and resolve complex integration challenges in healthcare technology.

The Senior Software Engineer will enhance the core product by developing features and tools for Chainguard Images, collaborating with teams and ensuring product quality.

Design, implement, and maintain scalable, secure, high-performance backend systems and public-facing APIs. Collaborate with Product and Data Science teams, lead initiatives improving efficiency and system performance, and support customer satisfaction. Work may involve distributed systems, pricing engines, identity management, authentication, authorization, API versioning, deprecation, and rate limiting.

Develop and maintain enterprise full-stack applications using Java Spring Boot, REST APIs, modern front-end frameworks, Oracle Exadata, and OpenShift/Kubernetes. Responsibilities include legacy code analysis, full-lifecycle development and testing, SQL and PL/SQL optimization, microservices deployment, CI/CD, code reviews, architecture discussions, monitoring, and Agile collaboration. The role requires an active transferable IRS MBI moderate-risk public trust investigation, U.S. citizenship, and substantial full-stack and cloud-native development experience.

Owns maintenance and support of Virscidian’s existing software products. Responsibilities include resolving defects and customer issues, developing C#/.NET desktop and server applications, working with SQL Server and REST APIs, supporting Azure resources and DevOps processes, troubleshooting deployments, and delivering incremental features. The role collaborates with support, product, business, and engineering teams while contributing to SaaS, scientific algorithms, performance, and scalability initiatives when appropriate.

Build and own Android growth and monetization experiments across subscriptions, pricing, advertising, purchases, and upgrade flows. Partner with product, design, data science, and analytics to instrument experiments, manage staged rollouts, monitor performance, and act on results. Use AI tools throughout development, contribute to Android architecture and engineering practices, participate in on-call support, mentor engineers, and help scale reliable mobile experiences to tens of millions of users.

Design, develop, and maintain scalable billing and invoicing systems using C# and PHP. Lead architecture, code reviews, mentoring, CI/CD improvements, monitoring, database optimization, security, and PCI DSS compliance. Use Claude and Cursor in daily development while validating generated code for correctness, security, performance, and maintainability. Collaborate across Product, Engineering, QA, and support teams to deliver reliable payment-processing services and resolve complex technical issues.