Top Senior Software Engineer Jobs in St. Louis, MO

Lead development of scalable Java software applications and high-availability services. Design architectures, solve complex system challenges, improve performance and scalability, and maintain quality standards. Collaborate cross-functionally, mentor junior engineers, own technical initiatives, address support-driven issues, and implement robust testing practices for mission-critical IT operations products.

Design, develop, and enhance scalable Java software for NinjaOne’s IT Operations platform. Lead architectural decisions, build high-availability services, address scalability and technical debt, improve quality practices, collaborate across teams, mentor engineers, and own technical initiatives supporting millions of endpoints and servers.

Lead development of scalable Java applications and high-availability services. Design system architecture, solve complex scalability challenges, improve quality, mentor engineers, collaborate cross-functionally, and own technical initiatives supporting a global IT operations platform.

Build and enforce workload safety standards across Affirm’s Amazon EKS fleet. Responsibilities include Kubernetes resource management, workload isolation, disruption handling, cluster capacity analysis, policy automation, production debugging, incident response, fleet-wide rollouts, technical leadership, mentoring, and measuring infrastructure impacts on availability, latency, risk, and cost.

Lead frontend feature releases and own user experience, performance, testing, and production health for a React and TypeScript dental practice management platform. Collaborate with backend engineers using Java Spring Boot, develop AI-powered interfaces, integrate AI tools such as Claude, participate in code reviews, improve team efficiency, and estimate development work for timely delivery.

Build, ship, and maintain scalable iOS features used by millions of users. Responsibilities include writing Swift code with modern iOS frameworks, designing reusable components, managing asynchronous workflows, improving performance and reliability, debugging production issues, contributing to architecture and testing strategies, participating in code reviews, and collaborating with product, design, and engineering teams through release and iteration.

Designs, develops, configures, tests, documents, and supports Guidewire ClaimCenter and related applications, integrations, tools, and systems. Responsibilities include production support, incident and problem management, troubleshooting, root cause analysis, release management, technical design, automated functional and performance testing, code reviews, mentoring junior developers, vendor liaison work, and collaboration with architecture teams. The role requires independent judgment, leadership, SDLC expertise, and strong Java, .NET, JavaScript, SQL, Oracle, and testing capabilities.

Leads the design, configuration, development, integration, testing, deployment, and production support of Guidewire InsuranceSuite applications for Property and Casualty insurance. Translates business requirements into secure, scalable solutions; directs technical design and code reviews; supports integrations, incident resolution, root cause analysis, releases, and continuous improvement. Mentors engineers, maintains technical documentation, and promotes Agile, DevOps, quality, security, and enterprise architecture standards.

Build foundational advertising account systems for Netflix Ads, including advertiser data models, account hierarchies, enrichment, verification automation, cohort assignment, spend attribution, and customer-facing APIs. The role involves designing scalable, multi-tenant, API-first cloud services with strong governance, reliability, observability, and operational excellence. Engineers will make zero-to-one architectural decisions supporting sales workflows, media planning, programmatic integrations, and advertising growth.

Own and develop a TypeScript monorepo spanning Next.js, Expo, and Cloudflare Worker applications. Build secure PostgreSQL and Prisma systems, webhook handlers, background jobs, authentication, encrypted financial data workflows, and AI-powered financial features. Responsibilities include production ownership, incident response, code review, and ensuring reliability, security, idempotency, and data isolation across web and mobile products.

Build and ship end-to-end product features across an author analytics dashboard, marketing site, free tools, billing, email, and AI-assisted functionality. Design data models and APIs, integrate third-party services, develop production LLM features, and maintain testing, monitoring, performance, and observability. The role includes code review, technical documentation, independent product decisions, and close collaboration with the founder in a remote-first environment.

Leads development of resilient, scalable features across Toast’s enterprise Sports and Entertainment platform, including backend, frontend, and POS systems. Responsibilities include designing, deploying, testing, monitoring, and maintaining production services; leading complex technical projects; collaborating with Product, Design, Customer Success, Sales, and other teams; mentoring engineers; and using AI tools to improve development productivity.

Own and deliver highly available, low-latency backend identity systems supporting consumer onboarding, authentication, and verification. Lead quarterly team goals, guide engineers through ambiguous problems, collaborate with product and design partners, monitor system reliability, improve engineering standards, support on-call operations, and mentor team members. The role requires designing and launching distributed systems at scale using Python or Kotlin, AWS, MySQL, and Kubernetes.

Develop, integrate, test, debug, and maintain C/C++/C# embedded software controlling NDI and avionics automated test equipment. Responsibilities include hardware-software integration, UI updates, functional and unit testing, automation-tool development, test equipment sustainment, requirements traceability, and GitLab CI/CD pipeline maintenance. The role is fully onsite, supports commercial and military platforms, requires U.S. Person status and the ability to obtain a Secret clearance, and involves less than 10% travel.

The Senior Fullstack Software Engineer will design, implement, and maintain features for Conveyor's SaaS platform, involving both backend and frontend work, while collaborating closely with team members and mentoring juniors.

Design, build, and maintain AI-powered B2B SaaS products across frontend, backend, and AI. Own projects end-to-end, collaborate with product and design, ensure maintainability, mentor teammates, and inform roadmap and implementation decisions.

Build and own the technical roadmap: design AI-first interfaces and APIs, architect scalable ETL pipelines, develop data models for ML features, ship autonomous B2B workflows (PO generation, vendor sync, schedule optimizations), and establish engineering standards, CI/CD, and mentoring.

Build and scale Supabase Storage across client libraries, CLI, CDN, storage servers, and deployment infrastructure. Responsibilities include improving upload and download performance, asset optimization, edge networking, caching, observability, reliability, APIs, developer tools, and the storage explorer. The role also involves PostgreSQL and distributed-systems performance tuning, infrastructure operations, escalated support resolution, and end-to-end project ownership in an asynchronous, remote, open-source environment.

Build and own shared architecture, infrastructure, state-management patterns, testing systems, and developer tooling for a React Native mobile application. Deliver customer-facing features, integrate APIs and third-party services, resolve iOS and Android issues, optimize performance, and improve AI-assisted engineering workflows. Mentor engineers, review code, guide platform adoption, maintain reliability standards, and participate in production support and on-call rotations.

Develop and modernize a production React Native mobile application supporting offline-first workflows, BLE device integrations, synchronization, scalability, performance, and reliability. Design and maintain application features, contribute to architecture and engineering standards, collaborate cross-functionally, mentor developers, provide technical leadership, and engage with farm customers. Occasional travel to customer locations is required.

Build and architect Clear Street Active, a high-performance trading platform for active traders. Develop responsive web interfaces integrating real-time market data, low-latency execution workflows, and advanced trading tools. Collaborate with cross-functional teams on large-scale initiatives while emphasizing scalability, performance, API quality, maintainability, and developer experience.

Architect and build a high-performance trading platform for active traders. Develop responsive web interfaces integrating real-time market data, low-latency execution workflows, and advanced trading tools. Collaborate with cross-functional engineering teams on large-scale initiatives, emphasizing scalability, performance, API quality, maintainability, developer experience, and end-user usability.

Senior engineer responsible for designing, building, and operating scalable data ingestion, processing, storage, and member-facing membership application. Drive architecture decisions, mentor engineers, build data pipelines, APIs, and ensure reliability, observability, CI/CD, and documentation while partnering with product and analytics stakeholders.

Lead frontend and full-stack engineering, architect scalable features, integrate APIs and cloud services, optimize rendering and performance, establish engineering standards, conduct code reviews, and mentor developers. Collaborate with product, UX, and backend teams to deliver user-focused software while managing priorities in an ambiguous environment.

Owns medium-sized software features from design through deployment and maintenance. Writes tested, maintainable code; participates in code reviews, incident response, and root-cause analysis; collaborates with product, UX, QA, and engineering teams; improves development processes and tooling; validates AI-assisted work; and mentors junior engineers. The role requires strong software engineering fundamentals, modern development practices, clear communication, and experience delivering end-to-end features.