Top Senior Software Engineer Jobs in St. Louis, MO

Architect and build the Solver framework powering NEAR Intents, including solver competition, quote aggregation, execution workflows, and cross-chain infrastructure. Lead technical design, code reviews, architectural decisions, and globally distributed collaboration while ensuring low-latency, high-throughput performance. Shape solver economics and cryptoeconomic incentives, remain hands-on with coding and prototyping, and address complex distributed systems and blockchain challenges.

Design, build, and optimize scalable cloud and web software with focus on infrastructure, performance, and hardware integration for IoT devices. Collaborate with hardware teams to ensure connectivity and high availability, implement new features, and improve system efficiency.

Design, develop, test, implement, maintain, and support custom web applications and software solutions involving internet security, content delivery, APIs, and cloud computing. Build new applications and platform capabilities, improve existing functionality, contribute to automated unit, functional, integration, and end-to-end testing, and troubleshoot distributed systems and web services.

Develop automated software tests and system-wide automation infrastructure for distributed systems. Collaborate with developers and QA teams, create tests replicating real-world scenarios, improve testing methodologies, validate requirements and test coverage, and solve large-scale distributed systems problems using coding and related internet technologies.

Develop and deploy automated system tests for distributed systems, improve testing methodologies, validate test plans and cases, and collaborate with developers and QA teams. The role involves software QA, test automation framework development, root cause analysis, functional, stability, integration, and performance testing, plus solving large-scale systems testing challenges using programming and related internet technologies.

Design, develop, test, implement, maintain, and support custom web applications focused on authentication, authorization, and identity products. Build new applications and platform capabilities, improve existing functionality, automate product processes, and contribute to unit, functional, integration, and end-to-end testing. Collaborate on software architecture and development within agile teams while supporting solutions in laboratory and QA environments.

Develop and lead automated testing for software features and major releases on Agile teams. Design object-oriented automation frameworks, automate tests using Python or similar languages, perform white-box, black-box, functional, and performance testing, investigate defects, manage test lab environments, estimate testing efforts, mentor engineers, and report testing status.

Design, build, test, and operate production-grade, secure, and scalable software and services. Partner with customers to translate requirements into technical designs, drive engineering best practices (CI/CD, testing, observability), deliver end-to-end solutions, lead technical workstreams, and apply AI/LLM approaches where appropriate to produce production-ready outcomes.

The Staff Software Engineer will lead feature delivery by building frontend and backend components, focusing on architecture, optimization, security, and performance in a fast-paced environment.

Lead technical initiatives and architectural decisions for stream-aligned software teams. Build, evolve, and support scalable distributed web applications while applying software development, testing, security, data modeling, microservices, and API best practices. Collaborate with product managers and stakeholders to translate business goals into technical requirements, contribute to roadmaps and documentation, evaluate technologies, and mentor mid-level engineers in an agile environment.

Design, develop, and maintain scalable Python applications; collaborate with cross-functional teams to deliver features; ensure performance and quality; identify and fix bugs; maintain code quality and automation; lead and mentor team members using agile practices.

Develop and maintain multi-tier applications for a payment processing platform using C#, .NET, SQL Server, Azure, and related Microsoft technologies. Translate customer and product requirements into solutions, troubleshoot issues, recommend architectural and process improvements, and serve as a platform subject matter expert. Lead or support Scrum teams, mentor junior engineers, collaborate with global stakeholders, act as a customer point of contact, and uphold Agile, QA, SOLID, and CI/CD practices.

Build and own Pepper’s regulated audit platform across internal auditor tools, client and partner portals, data models, integrations, security, and reliability. Develop end-to-end features using TypeScript, React, Node.js, PostgreSQL, and Supabase. Design secure multi-tenant data isolation, authentication, audit logging, evidence integrity, integrations, observability, CI/CD, and deployment workflows. Partner with founders, auditors, CPAs, engineers, and external partners in a high-autonomy environment.

Design and implement high-performance distributed Rust systems for autonomous, human-machine-AI teaming in constrained and contested environments. Responsibilities include architecture, hardware and microcontroller integration, networking, deterministic build infrastructure, OTA updates, simulation and field testing, performance optimization, and deployment of reliable edge systems. The role supports mission-critical defense applications and requires collaboration across engineering, research, and operational teams.

Lead design and delivery of scalable, secure full-stack systems; mentor engineers; integrate AI-driven and agent-based workflows; ensure cloud-native, containerized deployments and secure SDLC practices.

Senior backend engineer responsible for designing and implementing scalable, high-availability backend services for investment and financial products. Work primarily on backend APIs, integrations with financial institutions, databases, testing, troubleshooting production issues, and contributing across the stack while focusing on performance, security, and maintainability.

Lead Software Engineer responsible for designing, developing, testing, and maintaining a distributed processing application using Python and Java. Collaborate with product owners, data coaches, analysts, DBAs, and Agile teams to meet backend/frontend requirements, implement cloud and big-data solutions (Spark/Hadoop), and ensure program standards and reliable delivery.

The Senior Software Engineer II will design scalable solutions, enhance application functionality, and collaborate with product managers to deliver features.

As a Senior Software Engineer (Backend), you will design and implement scalable applications, collaborate with agile teams, and mentor junior members while ensuring high code quality and performance.

The Staff Software Engineer will lead technical vision and execution, drive architectural decisions, mentor engineers, and ensure code quality and scalability.

Design and develop scalable backend services and APIs, building frontend applications, collaborating on features, and ensuring system reliability. Lead technical projects and improve engineering practices.

Build and operate full-stack, production-ready systems: design and ship AI-native mortgage automation, integrate third-party lending APIs, and architect scalable AWS infrastructure and job processing. Mentor engineers and ensure security, observability, and high reliability.

Lead architecture and stabilization of a large-scale, multi-tenant CRM SaaS: own reliability, data-sync correctness, and performance; write production code (~40-50%); drive migration toward event-driven microservices; define observability, CI/CD, and AI-assisted development; mentor senior engineers and coordinate cross-team initiatives.

Design, build, and operate CRM SaaS features across Angular, Node.js, and PHP services. Own integrations, data synchronization, and high-throughput workflows. Improve scalability, reliability, observability, CI/CD, and incident response while mentoring teammates and helping modernize the architecture toward event-driven microservices on AWS.

The Staff Software Engineer will lead technical projects, develop full-stack software, mentor teams, and drive product direction at Propel, focusing on impactful solutions.