Senior Python Developer (Onsite)

About the Role

We are seeking a Senior Python Developer to design, build, and support the modular services and REST APIs behind the EDGE V4 Calculation Engine. You will turn validated building science formulas, rules, and assumptions into accurate, maintainable, and testable Python components that serve global, high-volume use.

Key Responsibilities

Calculation Services and APIs

• Design, develop, enhance, and support modular Python services and REST APIs for the EDGE V4 Calculation Engine.

• Translate validated building science formulas, rules, assumptions, and dependency flows into accurate, maintainable, and testable Python components.

• Develop and integrate calculation capabilities for energy, water, materials, embodied carbon, baseline standards, scenario simulation, explainability, anomaly management, and cost-related functions, as prioritized by the product backlog.

Architecture and Data

• Build reusable calculation libraries, data models, validation rules, configuration services, and version-controlled datasets using Python, FastAPI, Pydantic, SQL, and PostgreSQL (or approved equivalent technologies).

• Integrate calculation services with the EDGE V4 application through well-defined API contracts, structured inputs and outputs, secure authentication, and reliable error handling.

• Optimize calculation performance, database queries, caching, asynchronous processing, and service scalability.

Quality and Testing

• Create and maintain automated unit, integration, regression, and API tests using PyTest (or approved equivalent frameworks).

• Support system integration testing and user acceptance testing.

Operations and Documentation

• Implement production-grade logging, monitoring, auditability, exception handling, retries, configuration management, and operational support procedures.

• Maintain technical documentation, API specifications, calculation traceability, data dictionaries, setup guides, deployment notes, and support runbooks.

Team Collaboration

• Participate in solution design, code reviews, backlog refinement, sprint ceremonies, release planning, deployment, defect resolution, and post-deployment support.

Required Qualifications

• Minimum 8 years of professional Python development experience delivering secure, scalable, production-quality backend applications or calculation services.

• Strong proficiency in modern Python, object-oriented design, modular architecture, reusable libraries, type validation, dependency management, and coding standards such as PEP 8.

• Hands-on experience developing REST APIs with FastAPI (or an approved equivalent), including request validation, API versioning, authentication, structured error responses, and OpenAPI documentation.

• Strong knowledge of SQL and PostgreSQL, including data modeling, queries, functions, indexing, transaction management, and performance optimization.

• Proven ability to identify opportunities for engineering automation and productivity gains using AI, Generative AI, intelligent agents, scripting, and developer tooling, with practical solutions that reduce manual effort, improve code quality, accelerate testing, and enhance team effectiveness.

• Experience with Pydantic, PyTest, importlib, caching, configuration management, and development of reusable Python utilities and packages.

• Experience translating complex formulas, business rules, dependency graphs, or scientific models into deterministic, traceable, and testable software components.

Preferred Qualifications

• Experience designing automated unit, integration, regression, and API tests, with disciplined defect analysis and test evidence.

• Experience with Microsoft Azure services, App Service or approved container platforms, Azure DevOps, CI/CD pipelines, secrets management, logging, monitoring, and application support.

• Strong understanding of secure software development, data protection, auditability, resilience, performance, and production support practices.

• Working knowledge of building science, energy and water efficiency, materials, embodied carbon, cost calculations, or sustainability standards.

• Ability to collaborate with product owners, architects, building science specialists, QA teams, UX teams, DevOps teams, and business stakeholders.

Excellent analytical, documentation, communication, and problem-solving skills, with experience working in Agile and multicultural delivery teams across time zones.

Cognizant is an equal opportunity employer. All qualified applicants will receive consideration for employment without regard to sex, gender identity, sexual orientation, race, color, religion, national origin, disability, protected Veteran status, age, or any other characteristic protected by law.