Top Senior Software Engineer Jobs in St. Louis, MO

Lead design and implement scalable backend systems using Node.js, build RESTful APIs, design SQL schemas, optimize performance, mentor engineers, deploy on Azure, and maintain CI/CD, security, and observability.

Lead design and operation of the Synapse Everywhere external API platform: define API surface and guarantees, translate product and clinical requirements into contracts, own reliability and on-call incident response, provide technical mentorship and code reviews, and design scalable, secure cloud-native solutions (k8s, LLMs) with strong developer experience.

Design, build, and optimize scalable real-time and batch data pipeline infrastructure. Develop backend features focused on reliability and performance, write well-tested code, review technical designs, and contribute to infrastructure across mobile, desktop, and server systems.

Design, build, and maintain scalable backend services in C#/.NET powering payment routing, connector management, and platform configuration. Build secure, observable APIs and high-volume transaction processing systems, collaborate across Product/AI/Engineering, mentor junior engineers, drive architecture and standards, and own full lifecycle from requirements to deployment.

Build, operate, and scale core data services and APIs to process, store, and deliver large-scale patient health records with low latency and high availability. Provide technical leadership, contribute to architecture and design, collaborate with product and engineering teams, and coach engineers.

Design, build, and maintain AWS-hosted backend services (Lambda, Fargate) using JavaScript/Node.js. Develop and monitor RESTful APIs, create CloudFormation IaC, manage S3 data, integrate with Salesforce (refactor LWC/Apex), collaborate with Product, and document deployments.

Lead delivery of high-complexity digital banking implementations: design and build Java Spring Boot microservices, REST APIs, cloud-native containerized deployments, data and DB migrations, event streaming, monitoring and performance optimization. Act as a customer-facing technical lead conducting code reviews, test strategies, and cross-functional coordination to resolve operational issues.

Join an early engineering hire at a growing SaaS platform for online communities. Scope and deliver new features, write modular TypeScript/React code, enable AI coding agents, monitor production, and troubleshoot issues while influencing product direction and improving platform scalability and developer experience.

Build and operate internal APIs and delivery systems for Data Science solutions. Implement deployment, security, auth, and observability; support integrations; runbooks and documentation; participate in on-call rotations, incident response, and post-incident improvements; provide code reviews and mentorship; design solutions on cloud, Kubernetes, and LLM-enabled infrastructure.

Lead design, development, testing, deployment, and support of cloud-based software products. Provide technical leadership and mentorship, translate feature requirements into implementation tasks, ensure quality (tests, performance, security), resolve technical risks and defects, and collaborate with stakeholders to deliver scalable microservices and AI-integrated features.

Design and architect cloud-first, full-stack, scalable SaaS products; provide technical leadership, mentor engineers, promote automated testing and CI/CD, integrate AI/ML features (LLM/RAG), ensure observability and security, and collaborate with product, operations, and support.

Design, build, test, and deploy features for high-traffic web applications across multiple sports reference sites. Work full-stack on CI/CD pipelines and data ingestion, own features/systems, triage production issues, mentor peers, and contribute to technical planning and security/compliance improvements.

Build and scale a global payments and treasury platform: design and implement resilient, event-driven microservices, client-facing APIs, and distributed systems; work with cloud infrastructure, container orchestration, message brokers, and relational databases to support high-volume money movement and financial ledgers.

The Staff Software Engineer will lead AI integration into software design, develop scalable systems, and mentor other engineers while improving best practices.

Lead remote engineering teams to design, architect, and deliver scalable, high-availability education technology platforms focused on content systems, workflows, and GenAI. Drive product and technical strategy, collaborate with product/design, implement cloud-native architectures, adopt agile practices, measure performance through data and testing, and continuously improve user engagement and platform reliability.

Lead QA activities for an IAM program: design and implement QA methodologies, create and run manual and automated tests, perform code/product reviews, triage defects, validate functionality/performance/security, and support CI/CD, UAT, and release validation across Agile teams.

The Senior Software Engineer will design and build fullstack features using Go, React, and Ember, ensuring optimal customer experiences and system scalability while mentoring peers and driving projects.

The Software Development Engineer II will develop navigation solutions, balance rapid development with reliability, and optimize performance while promoting operational excellence at Mapbox.

Lead the quality engineering efforts for Replicant's AI platform by defining standards, improving testing strategies, and mentoring a QA team to ensure high-quality outputs across software systems.

The Senior Software Developer will design and develop web and mobile applications, collaborate with scientists, implement APIs, and mentor developers.

Lead design and implementation of scalable backend systems that ingest, process, and serve high-volume health data. Own projects end-to-end, drive integrations with third-party APIs, improve data reliability and observability, mentor engineers, and partner with product, clinical, and data teams to deliver clinically meaningful insights.

The Senior Software Engineer will work on full-stack deliverables, manage support tickets, and enhance the tech stack for improved efficiency, focusing on analytics and automation in OOH advertising.

As a Senior Software Engineer, you will lead your team in delivering features according to specifications, ensuring scalable technical decisions, and mentoring team members.

Design and evolve systems for Motion's infrastructure, focusing on reliable and secure operations across APIs, Linux systems, and cloud environments with a focus on hands-on coding and engineering judgment.

Design and implement scalable frontend solutions using JavaScript/TypeScript and React. Drive architecture discussions, ship features with minimal guidance, maintain code quality and styling standards, collaborate across agile teams, ensure performance and scalability, and manage end-to-end feature lifecycles in a fast-moving environment.