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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Principal Software Engineer - **Company:** Cedar Inc - **Location:** Chicago, IL, United States - **Experience:** Expert - **Contract:** Permanent contract - **Skills:** ASP.NET, .NET Framework, Microsoft Windows, Application Programming Interfaces (APIs), Artificial Intelligence, Amazon Web Services, Component-Based Software Engineering, Confluence, JIRA, HTML5, Automation of Tests, Microsoft Azure, C Sharp (Programming Language), Cascading Style Sheets (CSS), Code Generation, Profiling, Code Review, Databases, Serialization, Data Structures, Software Design Patterns, Linux, DevOps, Entity Framework, Protocol Buffers, HTTP Secure, PostgreSQL, Windows Presentation Foundation, Microsoft SQL Server, MySQL, Nunit, Object-Relational Mapping, OAuth, Object-Oriented Software Development, Performance Tuning, Windows PowerShell, Scrum Methodology, Systems Development Life Cycle, E2e Testing, Openid Connect, Software Engineering, Strategies of Testing, Wireshark, TypeScript, WebSocket, WebRTC, ReactJS, Cypress (Programming Language), AI Coding Agents, Git, Containerization, Webpack, Kubernetes, Information Technology, Playwright, Build Tools, Live Streaming, Npm(Software), Graphql, Web Technologies, Front End Software Development, React Redux, Claude, Restful APIs, Es2015, Grpc, Docker, Jenkins, Microservices - **Published:** November 7, 2026 - **Apply:** https://www.juju.com/job/28_25197_f31b1e1d5d96871847910000d3e1b2a1 ## About the Role * The ideal candidate has Bachelor's degree in Computer Science, Software Engineering, or a related STEM field. * 10+ years of hands-on experience in professional full-stack development, including modern web technologies and back-end services. * Demonstrated experience designing and leading integration and end-to-end test strategy for complex, multi-component systems. * Strong OOP skills, experience with design patterns, and a solid grounding in computer science fundamentals. * Experience mentoring engineers and providing technical leadership across teams. * Hands-on experience using AI coding assistants (e.g., Claude) in a professional development workflow. Additional Skills & Requirements * Expertise in ReactJS, React Hooks, MobX or Redux, and component-based architecture. * Strong proficiency in HTML5, CSS3, JavaScript (ES6+), and TypeScript. * Advanced experience with C#/.NET and ASP.NET for building robust back-end services. * Experience with front-end build tools such as Webpack, Babel, and NPM. * Proficiency in building and consuming RESTful APIs, gRPC, WebSockets, and other real-time communication methods. * Expertise in throughput optimization techniques, serialization (MessagePack, Protobuf), and compression methods. * Experience with microservices architecture. * Working knowledge of WPF desktop clients sufficient to build against, integrate with, and test them (e.g., the Silexx OEMS). * Strong understanding of data structures and algorithms, profiling, and performance optimization. Testing & Quality * Expertise designing and implementing integration, contract, and end-to-end test automation across web, API, and back-end layers. * Hands-on experience with test frameworks and tooling such as Playwright or Cypress, xUnit/NUnit, and API/contract testing tools. * Experience embedding automated tests into CI/CD pipelines as release gates. * Ability to define test strategy and quality standards that span multiple products and teams. AI-Augmented Development * Proficiency using AI coding assistants such as Claude for code generation, test creation, code review, and refactoring. * Familiarity with integrating AI and agentic tooling into the SDLC and establishing responsible-use practices for a team., * Expertise in implementing authentication and authorization using OpenID Connect, OAuth 2.0, and related security standards. * Experience with security code scanning and remediating identified vulnerabilities., * Proficient in database technologies such as MySQL, Postgres, and SQL Server, and ORM frameworks like Entity Framework. * Familiarity with Agile/Scrum methodologies and DevOps practices (CI/CD pipelines, automated testing, etc.). * Comfortable with Windows and Linux operating systems. * Excellent communication, problem-solving, and leadership skills., * Experience with financial industry systems, real-time trading, order routing workflows, or market data distribution. * Hands-on experience with desktop frameworks like Electron, Tauri, or OpenFin, or with native desktop / OS-level APIs. * Familiarity with GraphQL. * Containerization (Docker/Kubernetes) and cloud platforms (Azure, AWS, or GCP). * Experience with tools such as PowerShell, Git, Jenkins, Jira, Confluence, and Wireshark. ## Description * Serve as the subject-matter expert for integration and end-to-end testing, working across the Silexx, LiveVol, and DataShop teams to define and refine how we validate workflows that span the front-end, APIs, and back-end services. * Lead the design, architecture, and implementation of modern full-stack applications using ReactJS front-ends and C#/.NET back-end services. * Build and maintain automated integration, contract, and end-to-end test suites that exercise REST, gRPC, and real-time streaming interfaces across products, and wire them into CI/CD pipelines as release gates. * Leverage AI coding assistants such as Claude across the SDLC - for test generation, code review, refactoring, and agentic automation - and help establish team practices and guardrails for AI-augmented development. * Collaborate with product management and cross-functional teams across products to understand requirements and deliver integrated, high-quality solutions. * Implement secure server communications and authentication/authorization using RESTful and streaming protocols, OpenID Connect, and OAuth 2.0. * Drive technical decisions, provide architectural direction for growth into new asset classes and products, and mentor engineers across teams. * Diagnose and resolve complex, cross-product technical problems spanning the UI, API, and back-end layers.