Top Software Engineer Jobs in St. Louis, MO

Leads architecture, development, integration, testing, validation, and modernization of simulation frameworks, models, tools, and embedded real-time software. Serves as a technical expert for Boeing’s Test Development Kit, advises stakeholders on simulation requirements, integrates software with hardware, analyzes system performance, and oversees simulation software project activities. Requires extensive object-oriented development, modeling and simulation, Linux systems, and hardware-software integration experience.

Design and scale foundational APIs and backend services for LogicGate’s multi-tenant GRC platform. Build distributed systems using Java/Kotlin, Spring Boot, AWS, databases, caching, and messaging technologies. Improve reliability, observability, performance, testing, and CI/CD practices. Lead technical design reviews, collaborate cross-functionally, mentor engineers, and use AI coding tools to improve development efficiency.

Set technical direction for Toast’s Developer Experience platform, including local development, build tooling, shared libraries, testing frameworks, and developer portals. The role combines hands-on software engineering with architecture, cross-team technical leadership, AI-assisted development, developer productivity measurement, mentorship, and roadmap prioritization.

Build and ship core 0-to-1 systems connecting software, hardware, and finance. Responsibilities include designing abstractions over complex data and legacy systems, owning the full product lifecycle, developing production-grade LLM systems for loan underwriting and compliance, and contributing to engineering and product culture. The role requires strong backend and systems thinking, with comfort in full-stack development and UI design.

Unpaid software engineering internship focusing on full-stack web development with TypeScript, Next.js/React and Node/Express. Work on front- and back-end features, responsive UI with Tailwind, animations with Framer Motion, PostgreSQL and MongoDB integration, REST APIs, microservice-based architecture, code reviews, debugging, and product planning in a remote-first startup.

Develop, deploy, and support full-stack applications using React, JavaScript or TypeScript, C#, .NET, relational databases, REST APIs, and Azure. Partner with business users to modernize prototypes into secure, scalable production applications. Apply enterprise architecture, authentication, authorization, security, performance, and vulnerability-management practices. Build integrations, troubleshoot production issues, and collaborate with infrastructure, security, data, and architecture teams. Use AI-assisted development tools such as Claude Code and Codex extensively.

Develop scalable Java-based distributed systems for BILL’s Growth team, focusing on customer acquisition, activation, onboarding, and product expansion. Build high-performance SaaS applications using AWS services, SQL and NoSQL databases, Gradle, and CI/CD pipelines. Collaborate with feature teams and product managers while applying generative AI and LLM technologies to accelerate engineering workflows.

Develop firmware, backend systems, and tooling for cellular IoT devices. Responsibilities include C development for STM32 microcontrollers, embedded AI integration, cellular communication, low-power optimization, device debugging and validation, and backend development with Python and Ruby on Rails. The role collaborates with hardware, electronics, and manufacturing teams and requires independently leading complex development initiatives.

Builds and maintains custom software applications using .NET, Java, and JavaScript technologies. Responsibilities include software design, coding, debugging, testing, troubleshooting, and developing web-based and client-server systems. The role handles complex technical projects autonomously, may provide technical consultation and team leadership, and requires strong collaboration and communication skills. Travel up to 15% is expected.

Builds and maintains custom software applications, performing design, coding, debugging, testing, troubleshooting, and technical consultation. Works autonomously on advanced projects, may lead work groups, and follows coding standards and technical designs. The role supports web-based and client-server systems and requires strong collaboration and communication. Up to 15% travel is expected.

Build and ship customer-facing digital platform features for Slate’s direct-to-consumer EV brand. Responsibilities include designing, coding, testing, reviewing, and owning the quality of software components; integrating third-party APIs; collaborating with product and UX teams; solving problems independently; and supporting teammates through knowledge sharing.

Senior backend engineer responsible for designing and implementing new features, scaling and optimizing the platform, improving Postgres and Elasticsearch performance, fine-tuning LLMs, and making architectural decisions. Collaborate with engineering team, take ownership of features, write performant, maintainable code, and help shape product and infrastructure for data-intensive applications (NLP, search, indexing).

Develop and deliver native iOS features for MyFitnessPal’s Cal AI food-logging experience. Responsibilities include building interfaces in Swift, optimizing UI, storage, and network performance, implementing tests, researching technical solutions, collaborating with product and design teams, promoting engineering best practices, and mentoring junior developers.

Develop and lead frontend platform engineering for native and hybrid mobile applications. Build reusable, well-tested Android and iOS SDK components, contribute to architecture and system design, collaborate with product and engineering teams, own customer-facing deliverables, and identify product improvements while maintaining strong engineering standards.

Develop scalable backend software for lending infrastructure supporting loan origination, funding, servicing, and sales. Responsibilities include designing software modules, writing and testing maintainable code, building distributed and event-driven systems, participating in code reviews, and collaborating with senior engineers and cross-functional teams. The role uses C# or Python, relational and document databases, AWS, Docker, and Kubernetes, with emphasis on reliable, compliant financial technology.

Designs, develops, tests, deploys, operates, and maintains scalable full-stack software products. Builds React-based enterprise applications, writes production-ready code, performs code reviews, improves reliability and performance, integrates APIs, and follows security, compliance, accessibility, and DevOps practices. Collaborates across teams using agile methods, analyzes failures, prioritizes work, and contributes to technology transformation and continuous improvement.

Develop responsive ERP front-end interfaces using JavaScript, React.js, HTML, and CSS. Integrate RESTful APIs with PostgreSQL backends, translate UI/UX designs into functional applications, support API contracts and end-to-end testing, collaborate on CI/CD and containerized environments, document technical solutions, and maintain reusable components and libraries.

The role involves designing, developing, and maintaining software applications. Collaboration with cross-functional teams is expected, alongside optimizing existing systems.

Develops, tests, supports, and maintains scalable web applications and software components across front-end and back-end technology stacks. Partners with Product Management to design solutions, contributes to Agile planning and architecture, troubleshoots deployed products, reduces technical debt, and provides technical guidance to less experienced engineers.

Develops and maintains virtualized mission applications for VDI and thick-client environments using Citrix, VMware, and Microsoft technologies. Responsibilities include application sequencing, testing, user-settings persistence, automation, infrastructure configuration, disaster recovery, patching, troubleshooting, performance tuning, incident resolution, and technical documentation. The engineer works onsite with intelligence customers, operates independently, supports application delivery, and provides training and design materials.

Design and develop highly available, fault-tolerant distributed edge computing platforms using Go, Kubernetes, microservices, and cloud technologies. Build scalable APIs, troubleshoot complex systems, conduct code reviews, optimize performance and security, collaborate cross-functionally, mentor engineers, contribute to planning, and maintain technical documentation.

Develop and maintain scalable SaaS solutions for financial reporting and capital markets customers. Responsibilities include full-stack development, system design, testing, monitoring, performance optimization, security, technical debt reduction, and collaboration with product managers, developers, and SRE teams. The role requires building reliable, secure, maintainable data-driven applications and contributing across the software development lifecycle.

Lead architecture and engineering for a new Provider Onboarding team. Build scalable, database-backed systems and custom tools supporting pricing, payments, client panels, and forms. Establish engineering practices, mentor senior engineers, guide cross-functional delivery, and oversee the full software development lifecycle from planning through post-launch maintenance. The role requires healthcare systems experience and ownership of complex, reliable products.

Lead architecture and development for a new Provider Onboarding engineering domain. Build scalable full-stack, database-backed applications and microservices supporting pricing, payments, client panels, forms, and provider workflows. Mentor engineers, establish design patterns, drive cross-functional delivery across the full software lifecycle, and improve operational reliability for a healthcare platform.

Lead the technical direction of Samsara’s shared geospatial platform. Build scalable data ingestion and processing pipelines, map data models, spatial APIs, map-matching and routing foundations, and reusable platform capabilities. Scale storage, querying, and computation for real-time features, consolidate team-specific solutions, mentor engineers, lead cross-team technical projects, and represent the company in the geospatial community.