Backend Engineer

Senior AI Backend Engineer (Python/FastAPI, Agentic AI & LLM Applications)Job Type: Contract
Contract Duration: 6 Months
Pay Rate: CAD $90-100/hour (depending on experience and alignment)
Location: Hybrid, 1 day onsite weekly, Downtown Toronto, ON
Your New CompanyOur client is investing in next-generation AI-powered applications and is expanding its engineering team with experienced contractors who can help design, build, and scale production-grade AI solutions. This is an opportunity to work on innovative Agentic AI initiatives involving Large Language Models (LLMs), cloud-native architectures, API integrations, and modern AI orchestration frameworks.
Your New RoleAs a Senior AI Backend Engineer, you will be responsible for designing, developing, and deploying production-grade AI applications and backend services. You will build scalable Agentic AI workflows, integrate Large Language Models, and contribute to cloud-native solutions that support enterprise-scale applications.Working closely with engineering leadership and technical teams, you will help architect intelligent systems leveraging modern AI frameworks, retrieval systems, cloud services, and observability tooling.
Key Responsibilities

• Design and develop scalable backend services and APIs using Python and FastAPI
• Build production-grade AI applications leveraging Large Language Models (LLMs)
• Design and implement Agentic AI workflows and autonomous agent systems
• Develop and maintain Retrieval-Augmented Generation (RAG) solutions
• Integrate external and internal services through REST APIs
• Implement LLM tool calling, structured outputs, and workflow orchestration
• Build and optimize cloud-native applications utilizing GCP, AWS, or Azure
• Develop integrations with BigQuery, databases, vector stores, and enterprise systems
• Containerize and deploy applications using Docker and modern CI/CD pipelines
• Implement authentication and authorization workflows for secure services
• Collaborate with architects, product teams, and developers on technical design and solution architecture
• Maintain performance, scalability, observability, and reliability of production systems
• Participate in code reviews, architecture discussions, and technical leadership activities

What You'll Need to SucceedRequired Qualifications

• 10+ years of software engineering experience
• Strong Python development experience building production-grade applications
• Hands-on experience developing backend services using FastAPI
• Experience building and deploying scalable REST APIs
• Experience building AI-powered applications utilizing LLMs
• Experience developing Agentic AI workflows and autonomous AI systems
• Hands-on experience with LangGraph and LangChain
• Experience implementing Retrieval-Augmented Generation (RAG) architectures
• Experience integrating AI services through REST APIs
• Experience with LLM tool calling and structured outputs
• Strong experience designing cloud-native applications
• Experience with Google Cloud Platform (GCP), AWS, or Azure
• Experience integrating applications with databases and data platforms including BigQuery
• Familiarity with Redis caching strategies
• Experience with authentication and authorization workflows (OAuth, JWT, SSO, etc.)
• Experience with Docker and CI/CD pipelines
• Strong understanding of software design principles, scalability, performance optimization, and secure coding practices

Preferred Qualifications

• Experience with Langfuse or similar AI observability platforms
• Experience with vector databases and semantic search architectures
• Experience developing multi-agent systems
• Experience deploying applications on GCP using services such as BigQuery, Cloud Run, GKE, Dataflow, or Cloud Storage
• Understanding of machine learning and data science fundamentals
• Experience supporting enterprise-scale AI applications in production environments

What You'll Get in ReturnYou will join a highly skilled engineering team working on innovative AI initiatives and modern cloud-native solutions. This engagement offers the opportunity to work with cutting-edge technologies including Large Language Models, Agentic AI architectures, LangGraph, LangChain, and GCP while contributing directly to the development of enterprise-scale intelligent systems.Compensation is competitive and commensurate with experience, with flexibility for exceptional candidates who demonstrate strong alignment with the technical requirements.
What You Need to Do NowIf you're interested in this role, click 'apply now' to forward an up-to-date copy of your CV, or contact us directly for a confidential discussion regarding this opportunity.If this job isn't quite right for you, but you are looking for a new position, please contact us for a confidential discussion on your career.
This posting is for an existing vacancy with the organization.AI may be used to screen, assess, or select applicants for the position.

This posting is for an existing vacancy with the organization.

AI may be used to screen, assess or select applicants for the position.

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