Senior Fastapi Developer Jobs in Fairfield, CT (NOW HIRING)

Role Summary: The Sr. Staff Software Engineer will be part of the new Product Engineering team tasked with designing and building the next generation of Agentic AI-powered products for SmartEquip. Acting as the Technical Lead and Primary Architect, you will be a hands-on leader responsible for the team's overall delivery. You will lead a small squad by decomposing complex product requirements into actionable tasks, providing deep technical mentorship, and guiding the architectural direction while remaining deeply embedded in the codebase.
Key Responsibilities:

• Technical Execution: Lead technical delivery by translating high-level product roadmaps into actionable development cycles. Partner with Product Owners to define scope and ensure high-quality output through rigorous code reviews and technical mentorship
• Transactional Microservices: Architect and develop high-concurrency backend services in Python (FastAPI/Django) to handle core business logic, including shopping carts, order processing, and complex transactional workflows
• Tool Engineering for Agents : Design and implement "Agent-Ready" APIs using Pydantic for strict type enforcement and OpenAPI/MCP for autonomous service discovery, allowing agents to execute business actions (like placing an order) with 100% reliability.
• Integration Frameworks: Build and maintain secure, scalable integration layers (OAuth2, Webhooks) to connect the SmartEquip platform with diverse customer ERP and procurement systems
• Observation-Friendly APIs: Implement advanced error-handling and "hinting" within API responses to allow autonomous agents to self-diagnose and correct invalid requests during complex multi-step tasks
• AI-Native SDLC: Actively utilize autonomous coding agents to plan, generate, and test backend code, maintaining high velocity while ensuring code quality through agent-assisted peer reviews.
• Security & Auth: Own the implementation of secure authorization protocols (JWT,OpenID Connect) to ensure that both humans and AI agents operate within strict permission boundaries
• Performance Optimization: Monitor and optimize API latency and database query performance (PostgreSQL/MS SQL) to support real-time interaction for both web/mobile apps and high-frequency agent calls.

Skills and Experience:

• 10+ years of Software Engineering experience, with a proven history of leading technical squads, architecting, and building complex transactional backend systems.
• Expert mastery of Python (FastAPI, Django) and proficiency in modern Front-end frameworks (Angular/Typescript).
• Deep mastery of RESTful API design, specialized in Tool-Calling patterns and structured data exchange for LLMs.
• Strong SQL skills (PostgreSQL/MS SQL) and production experience with OAuth2/JWT for secure service-to-service communication.
• Experienced in working with cloud platforms (GCP, AWS) and deploying containerized services that are secure and scalable.
• Demonstrated proficiency in using coding agents to accelerate the SDLC and plan and code complex engineering tasks.

About Us
RB Global (NYSE: RBA)
RB Global (NYSE: RBA) (TSX: RBA) is a leading, omnichannel marketplace that provides value-added insights, services and transaction solutions for buyers and sellers of commercial assets and vehicles worldwide. Through its auction sites in 13 countries and digital platform, RB Global serves customers in more than 170 countries across a variety of asset classes, including automotive, commercial transportation, construction, government surplus, lifting and material handling, energy, mining and agriculture.
The company's marketplace brands include Ritchie Bros., the world's largest auctioneer of commercial assets and vehicles offering online bidding, and IAA, a leading global digital marketplace connecting vehicle buyers and sellers. RB Global's portfolio of brands also includes Rouse Services, which provides a complete end-to-end asset management, data-driven intelligence and performance benchmarking system; SmartEquip, an innovative technology platform that supports customers' management of the equipment lifecycle and integrates parts procurement with both OEMs and dealers; Xcira, a leader in live simulcast auction technologies; and Veritread, an online marketplace for heavy haul transport.
RB Global full-time employees are offered medical, dental, vision, and basic life insurances. Employees are able to enroll in our company's 401k plan and RB Global will match 100% for the first 4% contributed. Employees will also receive 15 days of PTO each year.
About the Team
About the team - Corporate
As a global company, our corporate teams support billions of dollars in equipment sales every year.
In joining our corporate services teams, you will be ensuring the business runs smoothly in your respective verticals and supporting the overall business to achieve our core objectives.
Every day your work will make a difference in the way we run our business and in the way customers interact with us.