Top Principal Software Engineer Jobs in Chicago, IL

Technical individual-contributor leader designing and architecting cloud-native, microservices-based payment systems. Partners with product, mentors engineers, drives CI/CD, automated testing, and operational readiness while ensuring security, scalability, and cross-functional alignment within FinTech.

Lead development of a massively distributed edge compute platform. Design fault-tolerant systems, external APIs, high-throughput traffic routing, and Kubernetes-based resource management. Establish architecture standards, reliability metrics, security practices, and technical governance. Collaborate with AI/ML, hardware, networking, and security teams; communicate risks to executives; manage customer requirements; review code; and mentor engineers on distributed systems best practices.

Lead technical ownership of InfiniBand and GPU interconnect fabric operations for hyperscale AI supercomputers. Drive incident response, deep multi-layer debugging across hardware/firmware/drivers/OS, and define failure models, playbooks, telemetry, and automation to improve reliability, observability, and scalability of GPU clusters and platform SLAs.

Lead technical direction for Elastic’s core billing platform across cloud providers. Design and operate scalable billing systems, data pipelines, APIs, and PostgreSQL architecture. Improve reliability, observability, incident response, deployment, and CI/CD practices. Partner with SRE, Cloud Infrastructure, Product, Design, and Finance teams, guide architecture and roadmap decisions, review technical work, mentor engineers, and participate in on-call rotations.

Design, build, deploy, and maintain resilient, scalable production systems for Toast’s retail customers. The role sets long-term technical architecture and strategy, communicates technical direction, mentors senior engineers, improves engineering productivity, diagnoses performance issues, and drives initiatives amid ambiguity. Engineers collaborate directly with retail customers, visit stores, understand operational workflows, and use AI tools to improve development velocity and quality.

Leads end-to-end design, development, quality, and integration of complex software solutions and cloud services. Provides technical leadership for enterprise-wide projects, manages engineering processes, risks, dependencies, and delivery priorities, and writes code across the software ecosystem. Collaborates with multidisciplinary teams to deliver measurable, user-centric technology solutions, primarily supporting healthcare caregivers.

Designs and implements Go-based control-plane software for custom AI inference hardware. Responsibilities span system management APIs, Linux services, hardware interfaces, diagnostics, observability, security, firmware updates, distributed systems, and workload management. The role requires hands-on debugging across application, operating system, firmware, and hardware boundaries, plus technical leadership, mentoring, architecture, and production ownership. Regular on-site lab work includes server racking, system bring-up, hardware troubleshooting, and documentation.

Lead the technical vision and architecture for scalable, secure, high-performance distributed systems. Provide engineering leadership, mentorship, and architectural guidance while driving reliability, automation, CI/CD, security, performance optimization, and technical strategy. Investigate emerging technologies, oversee complex problem-solving, establish engineering standards, and collaborate with product and business stakeholders to align technology roadmaps with organizational goals.

Leads architecture and development of scalable Node.js SaaS applications and data products. Responsibilities include designing systems, translating stakeholder needs into technical backlogs, writing user stories, coordinating architecture decisions, supporting product planning, improving business processes, and mentoring engineers. The role also incorporates AI-assisted development, code review agents, LLM APIs, agentic workflows, and generative AI tools.

Designs, develops, and leads scalable healthcare software solutions involving transaction processing, interoperability standards, integrations, and data platforms. Provides hands-on engineering, architectural leadership, quality ownership, risk management, technical mentorship, and cross-functional collaboration. The role requires building high-performance cloud-based SaaS solutions using microservices and serverless architectures, while guiding engineering strategy and ensuring secure, reliable delivery.

Lead the architecture and hands-on development of C#/.NET backend services, APIs, microservices, and real-time data pipelines for a trading platform. Own API contracts, versioning, security, observability, performance, testing, and highly available production systems. Partner with client integration and frontend teams, troubleshoot complex issues, establish engineering standards, support customers, and mentor engineers. The role requires expertise in distributed systems, low-latency development, streaming, databases, CI/CD, and API security.

Design, evolve, and optimize Scala-based, low-latency trading services. Lead architecture for scalability and performance, tune JVM/Akka systems, enhance observability, ensure security and regulatory compliance, and mentor junior engineers while collaborating cross-functionally to support 24x7 high-volume trading.

Lead architecture and technical execution for Toast’s Payroll and Team Management products. Own authentication, authorization, and organizational hierarchy across a multi-tenant SaaS platform. Drive high-scale, full-stack initiatives, modern agentic development practices, integrations, technical strategy, quality standards, deployment practices, and cross-functional collaboration. Mentor engineers across teams and leverage AI tools and LLM integration to improve software development velocity and quality.

Design, develop, and maintain a native IBM i connectivity agent for Redwood RunMyJobs. Responsibilities include job submission and monitoring, spool and queue handling, CL/RPG invocation, security integration, API connectivity, troubleshooting, performance and reliability improvements, architecture, code reviews, testing, documentation, and collaboration with product and engineering teams. The role also requires validating AI-assisted solutions against authoritative IBM i documentation.

Lead development and operation of a scalable Kubernetes-based cloud-native platform. Shape the engineering roadmap, deliver enterprise platform capabilities, establish best practices, mentor engineers, and collaborate across Agile teams. Build highly available and fault-tolerant production services using Kubernetes and cloud-native technologies, while applying expertise in Go, Python or Bash, networking, Linux, and CI/CD practices.

Owns end-to-end production software, architectural decisions, and improvements to the engineering lifecycle. The principal engineer will expand AI-assisted development, make speed safe across reservations, payments, mobile, and international systems, and influence a growing team’s engineering practices. Success means enabling a fourteen-person team to ship with the effectiveness of a much larger organization.

Lead the architecture and implementation of scalable cloud compute functionality across ARM64 and x86 platforms. Design hypervisor layers, cross-platform build pipelines, and performance optimization solutions while writing, reviewing, documenting, and testing production software. Coordinate globally to deliver compute features and resolve low-level software issues. Provide technical, organizational, and functional leadership to engineers.

Owns VM and fleet test strategy, performance quality gates, and hypervisor validation for an IaaS platform. Designs reproducible bare-metal-like test environments, develops automated performance benchmarks and regression gates, validates SLOs and deployment safety, and builds test harnesses and analysis pipelines in Go, Python, and Perl. The role requires deep expertise in virtualization, Linux systems, performance engineering, statistical analysis, and cross-architecture debugging.

Lead design, build, deployment, and operation of highly resilient, high-throughput configuration and publishing systems. Define long-term architecture and strategy, mentor senior engineers, diagnose and fix performance bottlenecks, and leverage AI tools to improve engineering productivity and platform capabilities.

Lead the technical vision, architecture, and roadmap for Pika’s web and multiplatform creative products. Design scalable user-facing systems, real-time collaboration, messaging, generative AI workflows, and cross-service observability. Partner with product and design leaders from ideation through launch, while driving architecture reviews, technical excellence, mentorship, and engineering strategy.

Design and build Seeq’s internal platform, including infrastructure, services, multi-tenant Kubernetes clusters, system interfaces, and secure deployment capabilities. Improve scalability, reliability, software delivery, and infrastructure cost and performance. Lead migrations, integrate security practices, architect distributed systems, collaborate cross-functionally, and mentor engineers while remaining hands-on at Staff or Principal scope.

Provides hands-on technical leadership for Pantheon’s P1 zero-to-one product and company-wide engineering strategy. Owns architecture across real-time collaboration, APIs, data, publishing, integrations, and developer experience; establishes reliability, security, observability, and delivery standards; guides build-versus-buy decisions; mentors senior engineers; partners with product, design, security, infrastructure, and customers; and contributes code to validate architecture and unblock critical initiatives.

Leads full-stack architecture and development across React, C#/.NET, WPF, APIs, and real-time systems. Owns integration, contract, and end-to-end testing across multiple financial products, embedding automated tests into CI/CD release gates. Implements secure communications, optimizes performance, guides architectural decisions, uses AI coding assistants throughout the SDLC, resolves cross-product issues, collaborates with product teams, and mentors engineers.

Develop and maintain embedded software and firmware for defense systems. Responsibilities include requirements analysis, software design, C++ coding, testing, debugging, integration, and lifecycle support on Linux or VxWorks. The role involves working with customers and technical teams, applying Agile or Waterfall methods, and integrating software with target hardware. The position is full-time and on-site in Rolling Meadows, Illinois, supporting mission-critical targeting, RF, and MSS products.

Develops, integrates, tests, and maintains embedded software and firmware for defense systems. Responsibilities span the full software development lifecycle, including requirements, design, coding, debugging, testing, integration, and supporting target hardware. The role uses C++ with Linux or VxWorks and applies software engineering standards, DevSecOps, model-based engineering, and Agile practices. It requires collaboration with customers, suppliers, users, and technical teams and is full-time, on-site in Rolling Meadows, Illinois.