Senior Python Backend Engineer — FastAPI & PostgreSQL (On-site DC)

Dexian DISYS; Washington (District of Columbia); On-site; USD 130,000 - 180,000; Full time

Job summary

Dexian seeks a technically strong Python backend developer for an on-site role in downtown Washington, DC. You will design, develop, and optimize modular Python services and REST APIs using FastAPI, Pydantic, and PostgreSQL, while aligning with product goals.

You will participate in solution design, code reviews, and release planning, ensuring production-grade logging, security, and reliable operation for global, high-volume calculations.

Qualifications

• 8+ years of professional Python development delivering backend services.
• Proficient in REST API design with FastAPI and OpenAPI documentation.
• Strong SQL/PostgreSQL knowledge including data modelling and indexing.
• Experience with Azure DevOps, CI/CD pipelines, and cloud deployment.
• Ability to translate complex formulas and rules into deterministic software.

Responsibilities

• Design, develop, enhance, and support modular Python services and REST APIs.
• Translate building science formulas and rules into Python components.
• Develop calculation capabilities for energy, water, embodied carbon, and cost functions.
• Build reusable libraries, data models, and version-controlled datasets.
• Integrate services through secure API contracts and robust error handling.
• Optimize performance, queries, caching, and asynchronous processing.
• Create automated tests (unit/integration/API) and support system tests.
• Maintain documentation, API specs, and runbooks.
• Participate in solution design, code reviews, and release planning.

Skills

Python development

REST API design

SQL & PostgreSQL

OpenAPI docs

Azure DevOps / CI/CD

Code quality (PEP8)

Unit testing (PyTest)

Agile delivery

AI / automation tooling

Education

Bachelor's degree in Computer Science or related

Tools

FastAPI

Pydantic

PyTest

OpenAPI

Azure

PostgreSQL

Job description

Dexian seeks a technically strong Python backend developer for an on-site role in downtown Washington, DC. You will design, develop, and optimize modular Python services and REST APIs using FastAPI, Pydantic, and PostgreSQL, while aligning with product goals.

You will participate in solution design, code reviews, and release planning, ensuring production-grade logging, security, and reliable operation for global, high-volume calculations.