Top Software Engineer Jobs in Washington DC,

Lead and architect front-end and full-stack features, balancing performance, accessibility, and maintainability. Partner with design, back-end, and product teams, mentor junior developers, improve tooling and workflows, review code, and evaluate emerging tools (including AI) to deliver high-quality interactive experiences.

The Senior Software Engineer will design and develop solutions on Salesforce, support software maintenance, and mentor junior engineers while driving feature development and business analysis.

The Senior Software Development Engineer will modernize a healthcare payer application using .NET and Angular, integrate AI models, and mentor junior engineers while working independently on complex tasks.

Lead architecture and development of high-performance, scalable backend systems for Yahoo Mail using Java and C++. Set technical strategy, establish architectural standards, validate AI-generated code, mentor senior engineers, collaborate cross-functionally, and ensure reliability through automated logging, telemetry, and debugging workflows.

Freelancer or small team to perform ongoing Shopify theme edits (PDP/buy-box), design and implement landing pages, create Klaviyo email templates and light technical setup, set up and iterate A/B tests, and run fast, safe small experiments to improve conversion without a full site rebuild.

Build and maintain ZODL's core Rust-based wallet and infrastructure (Zallet and core libraries). Implement protocol features from specifications, improve performance and reliability, support mobile teams, participate in reviews, testing, releases, and respond urgently to bugs and security issues.

Lead backend architecture and implementation for a healthcare scheduling platform rebuild: build FastAPI service controllers and Pydantic schemas, port legacy Python services to FastAPI/SQLAlchemy, own PressW-side cloud infrastructure (EKS, networking, IAM, observability), coordinate migrations and translation layers, drive code quality and testing, and mentor mid-level engineers.

The Full-Stack Developer will design and implement solutions for collaboration platforms, focusing on backend architecture, React-based front-end development, and integrating AI features. Responsibilities include developing services, APIs, user interfaces, and ensuring integration with various systems while utilizing Azure tools.

As a Backend Engineer, you will develop and scale PostHog's billing system to support growth, implement flexible billing models, and ensure accurate financial reporting. You'll focus on automating processes and handling complex data modeling.

Develop, configure, and maintain Salesforce solutions (LWC, Apex, Flows, OmniScripts, integrations) to support PMO operations; build reports/dashboards, configure Service Cloud and Experience Cloud, perform UAT/QA, and support data models, security, and email/notification automation per Government direction.