Top Software Engineer Jobs in St. Louis, MO

Paid, full-time software engineering internship supporting Microsoft 365 collaboration tools. The intern will help administer and troubleshoot SharePoint Online, OneDrive, Power Apps, and Power Automate; respond to user support tickets; gather business requirements; develop applications and workflows; research platform features; and document solutions. The role includes mentorship, professional development, networking, and cross-functional internship activities.

The role involves designing, developing, testing, and maintaining non-embedded software for air domain missions, leading junior engineers, and conducting integration testing.

Design, architect, and develop simulation models, virtual environments, and frameworks. Validate, integrate, modernize, and test simulation software and legacy systems, collect and process data, document algorithms and specifications, and collaborate with cross-functional teams to enable system integration and optimize performance in a secure Agile environment.

Design, develop, optimize and maintain ERP financial applications using Oracle and PL/SQL. Integrate systems, ensure security/compliance, resolve defects, lead code reviews, mentor junior developers, participate in Agile/Scrum, and estimate and deliver ERP features.

Develops and maintains safety- and mission-critical embedded flight software across the full software lifecycle, including requirements, architecture, coding, hardware integration, testing, debugging, verification, and documentation. Works in Agile integrated product teams and CI/CD DevSecOps environments, supporting capabilities such as sensor fusion, mission management, fire control, tactical communications, and supplier integration. The role also involves embedded software performance analysis, systems integration, compliance tracking, and project management functions.

Develops software architecture, requirements, algorithms, interfaces, and code for flight simulation systems. Builds simulation infrastructure, subsystem messaging tools, aircraft capability models, and testing environments. Integrates software components, documents research and development, and collaborates on an Agile team supporting defense and avionics programs.

Designs, develops, tests, and maintains non-embedded software for autonomous systems and advanced mission planning. Responsibilities include translating customer requirements, developing use cases and interfaces, conducting architecture trade studies, performing unit and integration testing, supporting system and flight testing, documenting software, and leading junior engineers. The role involves collaboration across programs, peer reviews, Agile development, and compliance with customer, safety, and regulatory standards.

Design, develop, test, and maintain embedded software for weapons programs. Translate requirements into software designs, create interfaces, perform unit/integration testing, participate in peer reviews, support system integration and test, and produce software documentation.

Develops, tests, maintains, and integrates non-embedded software for the Tomahawk missile program. Responsibilities include translating customer requirements into software designs, troubleshooting user issues, implementing technologies and regulatory changes, conducting research and development, debugging products, and documenting work. The role requires collaboration within a regulated defense environment and an active Secret clearance with eligibility for TS/SCI.

Develop backend prototypes, APIs, data-processing pipelines, and scalable server applications. Design application architecture and infrastructure for communications, logging, alerts, authentication, and configuration. Build test suites, optimize databases, support distributed and event-driven systems, and collaborate with users and developers to define solutions. The role is fully onsite, supports Boeing Defense Services, and may evolve into full-stack development. Up to 10% travel is required.

Paid, full-time software engineering internship supporting customer-context data patterns, decision-engineering tools, requirements analysis, and data-platform product development. Interns spend approximately 80% of their time on department projects and 20% on professional development, networking, mentorship, community service, and presentations. The role runs for 11 weeks during summer 2027.

Design and implement backend APIs, microservices, and checkout platform components for Affirm’s financial products. Own system health, improve performance and reliability, collaborate across engineering teams, and contribute to technical standards, tooling, and processes. The role requires developing, testing, and shipping high-quality software at scale while making customer-centric technical decisions.

Develops and leads software design, coding, testing, integration, requirements traceability, code reviews, verification, and deployment for Boeing Phantom Works solutions. The role collaborates with stakeholders, resolves technical risks, evaluates team and supplier performance, and mentors junior engineers. Work involves Java or C++, MATLAB, DevSecOps tools, Agile development, and complex space-based mission applications. An active Top Secret clearance and U.S. person status are required.

Lead design and implementation of backend systems for Model-Based Engineering web applications. Build APIs, data-processing and analytics pipelines, optimize SQL, develop production-ready infrastructure, create test suites, mentor engineers, participate in architecture and tech selection, and ensure scalability, resilience, and performance for large-scale distributed systems.

Design, develop, test, and maintain embedded application software for air-domain missions. Translate customer requirements into software architecture, perform unit/integration testing, support system integration and verification, participate in peer reviews, and produce software documentation while meeting safety, regulatory, and customer standards.

Design, develop, test, and maintain embedded software for weapons programs. Translate requirements into designs, develop interfaces, perform unit/integration testing, support system integration, participate in peer reviews, and create documentation while meeting safety, security, and regulatory standards.

Develop, document, unit test, integrate, and maintain software components for F-15 mission planning systems using C#, JavaScript, and SQL. Troubleshoot defects, collaborate on solutions, follow Agile/Scrum, and work under general supervision to compile builds and test components.

Develops, integrates, tests, maintains, and troubleshoots mission-planning software for defense systems. Translates customer requirements into software designs, supports architectures and system integrations, resolves technical issues, and improves software processes within Agile environments. The role requires C# and .NET development, version control experience, U.S. citizenship, and eligibility to obtain a Secret clearance.

Develop and maintain backend services for OppFi’s financial technology platform. Responsibilities include building Java applications and services, collaborating in an Agile environment, conducting code reviews and testing, documenting best practices, and refining technical requirements into production-ready solutions. The role uses AWS, Docker, PostgreSQL, APIs, and related cloud-native technologies.

Develop and scale backend streaming and data infrastructure using Kafka, Flink, AWS, Kubernetes, and related technologies. Break down projects, deliver tested software, collaborate with product and engineering teams, monitor system availability, participate in on-call support, debug code, conduct code reviews, and contribute to team development.

Build, optimize, and maintain software systems using AI while collaborating across disciplines on healthcare technology. Develop distributed, event-driven systems, learn new languages and frameworks, and protect user privacy through data security and HIPAA-compliant practices. The role works with AWS, Kubernetes, and large-scale medical datasets in a fast-paced, mission-driven environment.

Design, deploy, and optimize Philo’s distributed video streaming infrastructure, including ingest, transcoding, packaging, delivery, RESTful services, analytics pipelines, DRM, and ad insertion. Improve platform reliability, performance, latency, security, video quality, and cost efficiency. Collaborate with content partners and internal video, advertising, client, and data teams while supporting streaming quality across new platforms. The role also involves architectural ownership, cloud operations, and mentoring.

Paid, full-time software engineering internship supporting customer-context data patterns, decision-engineering tools, requirements analysis, and data-platform products. Interns collaborate with department teams, participate in professional development, networking, mentorship, and cross-functional activities. Candidates must be rising seniors pursuing a bachelor’s degree, maintain at least a 3.0 GPA, and be authorized to work in the U.S. without current or future employment-based sponsorship.

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.

Develop and maintain native iOS applications using Swift and SwiftUI for DraftKings’ financial platform. Responsibilities include building user-facing features, integrating APIs, managing data and state, optimizing performance, monitoring crash analytics, participating in code reviews and testing, and troubleshooting reliability issues. The role collaborates with product, design, analytics, and engineering teams to deliver scalable, compliant mobile experiences.