Top Senior C# Jobs in San Diego, CA

Design, develop, deploy, and maintain scalable cloud applications and client-installed agents using C# and .NET. Own platform integrations, troubleshoot production issues, optimize performance and costs, improve testing and automation, and uphold software security and quality. Collaborate with product, architecture, UX, support, and customers; contribute to technical and architectural decisions; and mentor engineers. The role also requires polyglot development across integrations and familiarity with cloud security, PAM, Azure, CI/CD, and automation practices.

Build and own scalable payments infrastructure for card issuing, transaction processing, and settlement. Design reliable integrations with Stripe, banking partners, and internal platforms using .NET, C#, Azure, DDD, CQRS, and event-driven architectures. Improve system reliability, observability, performance, security, and compliance while mentoring engineers and contributing to technical direction. Apply AI-assisted development across coding, testing, debugging, and engineering workflows.

Lead a multi-team engineering organization responsible for delivery, technical quality, production reliability, security, privacy, and AI-native development practices. Build scalable teams and managers, establish cross-team delivery systems, partner with Product and Design, oversee observability and incident response, use engineering metrics to guide improvements, and shape hiring, leveling, and talent development.

As a Senior Software Engineer, you'll develop and build tools for creative projects while leading feature development and collaborating with teammates.

Build scalable backend-heavy services and applications using C# and .NET, while contributing to Angular and TypeScript UI development. Design and develop REST APIs and microservices, work with relational databases, implement automated testing and CI/CD, and ensure system security, scalability, and performance. Preferred work includes event-driven architectures, messaging systems, NoSQL databases, caching, search technologies, and mentoring engineers or leading technical initiatives.

Lead backend and full-stack work on the Payments team, building multi-gateway integrations (Stripe, PayPal), payment APIs, and customer payment UIs. Ensure secure, compliant (PCI-DSS) payment flows, reliability, observability, and scalability across AWS/Kubernetes microservices. Partner cross-functionally to design architecture, implement settlement/reconciliation, and maintain high availability.

Designs and commissions automated robotic, CNC, and tooling cells from concept through production handoff. Responsibilities include PLC, robot, HMI, motion-control, electrical-panel, industrial-network, machine-vision, sensor, and safety-device integration. The engineer performs floor commissioning, risk assessments, root-cause analysis, and customer run-offs while collaborating with manufacturing, tooling, software, and program-management teams. The role also mentors engineers and technicians and develops reusable controls libraries and standards.

Develops, tests, documents, maintains, and enhances software solutions using established design principles and development practices. The role addresses defects, security vulnerabilities, and performance improvements; participates in requirements analysis, planning, and user story development; documents standards and changes; and collaborates with and mentors software engineers. Work involves .NET technologies, source control, software development lifecycle practices, and potentially Azure or AWS cloud development.

Designs, develops, documents, tests, and debugs software for the Next Generation Jammer program, including support equipment and simulators. Develops embedded, desktop, web, autonomous, scripting, and utility applications; analyzes system requirements; troubleshoots software issues; collaborates with subject matter experts; prepares operating instructions; and ensures software standards are met.

Develop and lead implementation of mathematical optimization models for supply chain applications. Investigate heuristics and optimization techniques, translate real-world problems into software, and design comprehensive testing strategies. Build robust C++ software, automated functional, regression, and performance tests, and collaborate with agile teams. Apply AI and other tools to accelerate development while maintaining architectural consistency, security, and code quality. Review AI-generated code for correctness, integration risks, and edge cases.

Develop and maintain automated testing tools and frameworks for complex healthcare software. Create test plans, execute white-box, black-box, UI, API, and performance testing, identify defects and testing gaps, improve CI/CD processes, and collaborate with product managers and developers to support high-quality releases. The role also involves debugging code, participating in demos, and working with distributed teams in a remote environment.

Leads the design, development, deployment, maintenance, and optimization of scalable full-stack software systems. Responsibilities include coding, debugging, code reviews, API development, cloud-native deployment, testing, monitoring, performance optimization, production support, incident response, technical mentoring, and establishing development standards. The role collaborates cross-functionally, drives API-first and AI-enabled engineering practices, and participates in on-call support.

Develop scalable, secure, performant web applications and data pipelines for healthcare technology. Partner with engineering, product, and business stakeholders on technical roadmaps, use Agile practices, improve observability and reliability, and mentor junior engineers through coaching and code reviews. Responsibilities include database querying, technical decision-making, API development, data ingestion, cloud technologies, containerization, CI/CD, and handling sensitive data.

Designs, builds, and maintains scalable backend services, APIs, databases, data flows, and infrastructure. Leads complex features from design through deployment while improving performance, observability, security, testing, and reliability. Integrates third-party platforms, supports cloud infrastructure and CI/CD practices, and mentors engineers through technical guidance and knowledge sharing.

Designs scalable, production-grade architectures for enterprise applications, distributed systems, cloud platforms, APIs, integrations, and data flows. Defines architectural standards, evaluates technology trade-offs, and guides cloud engineering, modernization, CI/CD, infrastructure as code, observability, security, and reliability practices. Provides technical leadership through design reviews, mentoring, client collaboration, solution shaping, and technical planning while supporting scalable and maintainable software delivery.

Leads and mentors the AgentMate application development team while remaining hands-on with C#/.NET development. Owns engineering execution, application security, PCI compliance, reliability, quality, observability, technical debt, and production support. Partners with Product, Delivery, Infrastructure, Security, QA, and business stakeholders to deliver secure, scalable applications. Responsibilities include architecture and coding, threat modeling, vulnerability remediation, CI/CD improvements, incident resolution, technical planning, documentation, hiring, and team development.

Owns end-to-end development and support of the Sage 300 ERP ecosystem, including customizations, .NET and Python applications, legacy VB6 maintenance, third-party integrations, SQL Server database design and optimization, reporting, and BI solutions. Collaborates with business and technical stakeholders, contributes to architecture, mentors junior developers, improves processes, documents solutions, and resolves production issues.

Develop and maintain high-volume, mission-critical enterprise web applications using C#/.NET, ASP.NET MVC, AngularJS, and SQL Server. Responsibilities include full lifecycle development, architecture and design participation, troubleshooting, performance and scalability improvements, AI-assisted workflow development, Agile collaboration, technical mentoring, and supporting multi-tier systems.

Lead end-to-end design, development, deployment, testing, and production support of enterprise web applications. Build scalable client/server architectures, ensure security and data governance, mentor team members, collaborate with product and business stakeholders, and own timely delivery and quality of solutions. Analyze data patterns and support reporting and selection workflows.

Designs, develops, and sustains secure REST APIs, ETL pipelines, middleware, event-driven integrations, and data validation services for DoD modernization. Optimizes schemas and data workflows, manages API gateways, monitors performance, troubleshoots synchronization issues, and ensures interoperability across IL2-IL5 cloud environments. Collaborates with cybersecurity, database, and Agile teams to meet DoD RMF, STIG, Zero Trust, and data governance requirements while maintaining integration documentation and supporting deployment validation.

Leads Agile development and sustainment of secure data integration solutions for DoD systems. Responsibilities include RESTful API design, data migration and validation, database optimization, data pipelines, analytics dashboards, integration testing, DoD compliance, CI/CD support, documentation, and mentoring. The role collaborates with cybersecurity teams on RMF and STIG controls while guiding technical delivery and Agile ceremonies in AWS GovCloud environments.

Develop and sustain a secure enterprise Case Management System for DoD stakeholders. Responsibilities include building CMS components, microservices, API integrations, workflow automation, and AWS GovCloud software; implementing DevSecOps and CI/CD; conducting code reviews, testing, data validation, and documentation; supporting Agile delivery; ensuring DISA STIG and RMF compliance; and providing Tier 2/3 production support.

Lead architecture and hands-on development of the end-to-end video pipeline (live ingest, transcoding, storage, playback, and developer SDKs). Mentor engineers, collaborate across mobile/web/ML/platform teams, own monitoring and on-call support, and help scale video streaming and VoD capabilities for millions of streams and clips.

Develop and maintain clean, reusable software using React and TypeScript. Contribute to front-end and back-end solutions, collaborate in an agile Scrum environment, use Git for version control, solve complex technical problems, and potentially lead development teams. The role supports a Navy customer and requires the ability to obtain a US Secret security clearance.

Build scalable full-stack applications integrating healthcare insights with browser-based and Windows EHR systems. Develop products using FHIR and HL7 interoperability standards, collaborate on technical roadmaps, and implement performant solutions. Mentor junior engineers, conduct code reviews, make technical decisions, and partner with engineering, product, and business stakeholders using Agile processes.