Top Senior Software Engineer Jobs in Madison, WI

As a Senior Software Engineer at Flex, you'll design and maintain financial services architecture, mentor junior engineers, and ensure scalability and security for innovative financial products.

Design, build, and operate full‑stack features and platforms for Horizon. Work across frontend, backend, infrastructure, data, and developer tooling; formulate solutions, ship production code, improve reliability and developer productivity, and expand AI/agent-assisted workflows. Collaborate with product, customers, and cross-functional teams, review code (including agent-generated), and improve internal tooling, observability, and deployment workflows.

Develop and maintain a digital ordering platform for medical equipment. Lead technical decisions, deliver quality code, and ensure system reliability while collaborating in an agile environment.

The Senior Software Engineer will architect and optimize AI-powered developer tools, enhance the SDLC, collaborate across teams, and mentor peers to improve engineering productivity.

Build and improve the end-to-end experience for new customers by implementing features across Python services, a GraphQL gateway, Auth0-based auth, and Terraform-managed GCP infrastructure. Collaborate cross-functionally to redesign discovery, evaluation, onboarding, and time-to-value while ensuring reliability, testing, and stable deployments.

Lead design, development, and maintenance of cloud hosting management and orchestration solutions. Mentor engineers, review code for quality and security, design REST APIs, troubleshoot issues, improve performance and reliability, and drive requirements and architecture decisions to enhance customer experience.

Lead backend development using C#/.NET and cloud-native technologies. Build and maintain APIs, ensure quality and performance, troubleshoot issues, conduct code reviews, and drive software/process improvements.

Build and operate backend systems enabling enterprise deployments of Coder. Design and implement scalable backend architecture, improve upgrade and migration reliability, investigate and resolve production scalability issues, own operator-facing backend features, document tradeoffs, participate in design reviews and on-call rotations.

Lead design, implementation, and operation of production-quality DevOps platforms and automated test infrastructure for heterogeneous edge hardware. Improve CI/CD, build/release, deployment automation, developer tooling, and platform reliability. Enable reproducible tests, diagnose failures across devices, partner with engineering and QA, and drive major infrastructure initiatives from ambiguity to production.

Lead design and implementation of high-throughput, low-latency programmatic bidding systems. Collaborate with ML engineers to deploy real-time inference, optimize distributed microservices, run experiments and quantitative analysis, and partner with product to ship scalable features. Foster operational excellence, mentor engineers, and continuously improve performance and reliability.

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.

Develop, configure, integrate, and operationalize command-and-control (C2) and Common Operating Picture (COP) applications. Build workflow automation, event management, alerting, data fusion, dashboards, and operator-focused UX. Support testing, interoperability validation, demonstrations, and operational readiness while collaborating with systems engineering and stakeholders.

Join cross-functional XP teams to deploy and adapt the Imogen platform into client public cloud environments. Pair-program, collaborate with client infosec and infrastructure teams, lead technical discovery, apply XP practices (TDD, CI/CD, pair programming), onboard and mentor engineers, build deployment tooling, participate in on-call rotations, and travel periodically for client engagements.

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, build, and own the Fastpath Assure connector for NetSuite (primary) and Oracle EBS/Cloud. Develop SuiteScript, saved searches, data extraction logic, and PL/SQL integration components. Drive roadmap, troubleshoot customer environments, collaborate with product and engineering, mentor engineers, and contribute customer-facing content and webinars.

Design, build, and operate highly scalable cloud-native microservices and web applications. Own features from design through production, improve observability, CI/CD, and cloud infrastructure, mentor teammates, collaborate across teams, and leverage AI developer tools to automate and accelerate engineering workflows.

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).

Design and build cloud-native, highly available systems and serverless applications on Azure. Implement Infrastructure-as-Code, develop TypeScript/React/NestJS applications, create APIs for web/mobile/IoT, write automated tests, deploy frequently, and participate in production support and on-call rotations while working in agile teams.

Senior individual contributor responsible for designing and building complex, customer-facing product features. Own technical decisions within product areas, collaborate with Product and Design, contribute to architecture, maintain code quality, mentor engineers, and participate in production support.

Design, build, and launch backend services to process and analyze clinical data at scale. Collaborate cross-functionally, enforce secure coding and privacy, support production systems, and drive technical improvements.

Senior Java engineer responsible for designing, developing, and maintaining scalable, secure backend systems using Java and modern frameworks. Participate in architecture, collaborate with product and security teams, write maintainable code, and adopt AI-assisted development tools while contributing to open-source efforts.

Build and operate scalable backend services and distributed systems for global payments. Design payment orchestration, ledgering, workflow engines, partner integrations, and public APIs. Own end-to-end projects, influence architecture and engineering standards, mentor teammates, and collaborate with product and engineering leadership to ship production-grade infrastructure.

Design, build, scale, and operate a Kafka-compatible, object-storage-backed streaming platform. Own backend services, storage engine, multi-tenant control plane, transactions and multi-region features. Troubleshoot complex distributed systems, ensure operational readiness and SLAs, participate in on-call rotation, and contribute across the full stack including developer console UI.

Design and build scalable backend services and distributed systems powering global payments. Develop payment orchestration, ledgering, workflow engines, partner integrations, and public APIs. Influence architecture, own projects end-to-end, collaborate with product, mentor engineers, and operate production systems.

Lead design and implementation of backend services and APIs for payments, billing, settlements, ledgers, and reconciliation. Drive architecture for highly available, auditable financial platforms, integrate with payment processors and banking partners, ensure transactional integrity, observability, and compliance. Deliver end-to-end initiatives, mentor engineers, and operate mission-critical systems with strong emphasis on reliability, security, and scalability.