Fullstack AI Engineer — Build Scalable AI Agents

Jobs in JS; Toronto; On-site; CAD 155,000 - 230,000; Full time

Benefits offered by this job

Health coverage

Equity

RRSP matching

Unlimited PTO

New York travel covered

Professional development stipend

Job summary

Solstice is hiring a Fullstack AI Engineer to build and maintain the agent platform, focusing on Python, FastAPI, and React/Next.js. You will own backend services, orchestration, and customer-facing interfaces in the Toronto office, with an initial on-site period and remote option later.

Collaboration with product, Applied AI, and engineering teams is essential. You will work across architecture, implementation, and production, delivering reliable AI workflows, tool access, and context delivery

Qualifications

• 5+ years of software engineering experience, including backend or fullstack work.
• Strong Python and FastAPI experience with async programming and API design.
• Solid understanding of data models, concurrency, and failure recovery.
• Experience turning AI into usable software and tool calls.
• Comfort with React/Next.js frontend and TypeScript.
• Ability to instrument systems with traces, logs, and metrics.
• Ownership mindset with strong collaboration skills.

Responsibilities

• Build and maintain the agent platform using Python, FastAPI, and Redis.
• Design APIs for content creation, document processing, and integrations.
• Ensure reliable long-running workflows with proper error handling and isolation.
• Develop frontend interfaces in React/Next.js to show progress and tooling activity.
• Make the system observable using tracing, logging, and metrics.

Skills

5+ years software engineering

Python

FastAPI

Distributed systems

React/Next.js

Observability & tracing

Ownership & judgment

Tools

PostgreSQL

Redis

Restate

Temporal

Job description

Solstice is hiring a Fullstack AI Engineer to build and maintain the agent platform, focusing on Python, FastAPI, and React/Next.js. You will own backend services, orchestration, and customer-facing interfaces in the Toronto office, with an initial on-site period and remote option later.

Collaboration with product, Applied AI, and engineering teams is essential. You will work across architecture, implementation, and production, delivering reliable AI workflows, tool access, and context delivery