Top Senior Software Engineer Jobs in St. Louis, MO

As a Senior Software Engineer, you'll implement collaboration features, support team architecture, work across tech stacks, and improve developer experience.

As a Senior Software Engineer, you will design best practices for AI Agents, develop standards, collaborate on product opportunities, and stay updated on emerging Agent techniques.

Drive the Continuous Integration team, ensuring build systems' reliability and scalability, and mentor CI engineers while improving developer productivity through automation and tooling.

The Senior Software Engineer at Order.co designs complex features end-to-end, mentors junior engineers, and participates in design reviews while ensuring quality and reliability of systems.

Build and own end-to-end full-stack systems for AI-powered agentic trading across web and React Native mobile. Implement real-time, low-latency UIs and Go backend services, integrate streaming AI/ML features and market data, drive architecture and code quality, and collaborate with AI/ML, design, and product teams to ship production-ready features used by millions.

Senior Software Engineer responsible for developing and maintaining web applications and microservices (React, Golang). Mentor team members, lead code reviews, influence technical decisions, improve CI/CD and testing strategies (unit, E2E, performance), collaborate across teams on integrations, and promote engineering best practices and documentation.

Lead technical design, build, and operate scalable, secure healthcare integration systems. Drive architecture, event-driven distributed systems, APIs, observability, IaC, CI/CD, incident response, cross-functional delivery, and mentor engineering teams.

Build and operate billing and payments services using Node.js/Go and Vue.js. Develop integrations with payment and accounting systems, ensure runtime reliability on AWS (SQS, Lambda), drive CI/CD and automated testing, write design docs and runbooks, mentor engineers, and optimize high-throughput, latency-sensitive workloads.

Design, build, and maintain scalable, secure backend services in Python. Implement SQL and NoSQL data models, CI/CD pipelines, and containerized deployments. Collaborate with product, front-end, and design teams, perform code reviews, optimize performance, troubleshoot production issues, mentor junior engineers, and improve development processes and infrastructure.

Develop and maintain spacecraft flight software across the full lifecycle: requirements, design, implementation, testing, integration with HIL and flight hardware. Build tools and simulations, perform subsystem and platform-level tests, support anomaly resolution, systems modeling, and proposal efforts while collaborating with manufacturing and customers.

Design, build, test, and maintain React Native features for Hertz consumer mobile apps on iOS and Android. Collaborate with cross-functional teams, integrate APIs and third‑party services, optimize performance, resolve production issues, contribute to CI/CD and testing, and improve mobile UX and accessibility.

Drive technical strategy and roadmap for Affirm's Online Storage platform. Design and build multi-region, highly available datastore solutions and control planes for hundreds of databases. Automate schema migrations, disaster recovery, sharding, and performance tuning. Collaborate with product, SRE, and infrastructure teams, own operations and on-call readiness, and mentor engineers while setting code and design standards.

Lead full‑stack engineering efforts to design, build, and operate production healthcare systems. Own epic-level features, mentor engineers, design for reliability and scalability, integrate with partners, and ensure launch readiness across backend (Java/Groovy), frontend (React/TypeScript), data (MongoDB), and event-driven pipelines (Kafka).

Design, develop, and maintain advanced software systems. Collaborate with product, design, and engineering teams. Write clean, scalable code, perform code reviews, debug complex issues, and stay current with technologies.

Lead end-to-end full-stack development across React frontends and compiled backends, influence architecture and data modeling, integrate third-party dealership APIs, use AI-assisted coding tools daily, set engineering standards, ship production features to live dealership users, and mentor junior engineers.

Design, build, and maintain Node.js backend services and APIs; integrate with front-end; optimize for performance and scalability; manage PostgreSQL and MongoDB databases; follow TDD and agile practices; perform code reviews and collaborate within a remote engineering team.

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.

Lead and set technical strategy for the Order Platform powering post-checkout flows (orders, captures, refunds, settlement). Design and ship highly available backend systems, own reliability/operational practices, mentor engineers, collaborate cross-functionally, and drive long-term technical decisions and execution plans.

Build and maintain the AI-powered learning platform across a TypeScript/React frontend and Python/FastAPI backend. Integrate LLMs for classification, extraction, personalization, and conversation practice. Design scalable APIs, develop real-time interactive features, apply AI-assisted development workflows, write well-tested code, and collaborate with product, design, and education teams to optimize learning experiences and A/B tests.

Define and own autonomy architecture for large-scale UAV swarms: design perception, planning, control, and inter-robot/C2 protocols; make system tradeoffs; mentor engineers; write production-quality code; support test events (up to 25% travel).

Lead design and implementation of scalable backend services and member-facing APIs using Python/Django, PostgreSQL, BigQuery/dbt and GCP. Own infrastructure as code (Terraform), container orchestration (Docker, Kubernetes), async/event-driven systems, observability, and performance tuning. Mentor engineers, collaborate with Product and Data teams, and ensure secure, low-latency, AI-driven member experiences.

Design, develop, and maintain cloud-native applications using Node.js and React. Implement infrastructure-as-code (Terraform/CDK), deploy CI/CD pipelines, troubleshoot Linux systems, ensure secure AWS deployments, and collaborate with cross-functional teams to operate cloud workloads.

Build and enhance full‑stack cloud-native applications using Java/Spring and JavaScript/React. Own the full SDLC, apply TDD and CI/CD, troubleshoot production issues, mentor junior engineers, and drive technical direction as experience increases from contributor to Lead.

Responsible for implementing and managing infrastructure as code (Terracore/Terraform), automating CI/CD with Jenkins, managing AWS services and Amazon EKS/Kubernetes, scripting in Bash/Python, implementing monitoring and security best practices, supporting production via on-call rotations, and collaborating with development and QA teams.

Join an early-stage platform team to scale and mature a mortgage origination platform. Work across the stack to improve distributed systems, performance, observability, and infrastructure tooling, and help define engineering standards and frameworks for growth.