Senior Full Stack Engineer

Job Description – Senior Full Stack Engineer

1. About the Role

Our client — a technology company based in Canada, specializing in Artificial Intelligence — is seeking a Senior Full Stack Engineer with strong technical expertise in AI platform development, automation, and fluent English communication skills to join their global engineering team.

You will contribute to building and scaling an AI platform / AI agent/automation system, designing intelligent pipelines and full-stack applications that bring real-world AI capabilities to production.

2. Responsibilities

Architect, build, and maintain full-stack applications powering AI platform and agent-based systems

Design and develop ReactJS frontend interfaces with a focus on performance, usability, and scalability

Build and maintain scalable Python REST APIs and backend services supporting AI workflows

Design and manage PostgreSQL databases including schema design, query optimization, and indexing

Develop and integrate AI agent/automation pipelines into the core platform

Work within SAS environments to support enterprise-grade AI workloads

Collaborate closely with product, data science, and infrastructure teams to deliver features end-to-end

Proactively identify and resolve performance bottlenecks, system stability risks, and scalability issues

Contribute to architectural decisions, coding standards, and engineering best practices

Stay current with the latest trends in AI, LLM, agent frameworks, and full stack development

3. Requirements

Must-have - backend

Python / FastAPI / SQLAlchemy / Pydantic in production, at depth. Owns a feature end to end: service layer, Alembic migration, REST endpoint, tests.

Async Python -genuinely understands asyncio, not just async/await syntax. We run both sync and async SQLAlchemy across our two applications and the difference matters.

PostgreSQL - joins, indexes, and multi-tenant row scoping.

Distributed-systems reasoning - retries, idempotency, partial failure, background jobs. Temporal itself is not required on day one; the ability to reason about that class of problem is, because within a few months this person reviews workflow-orchestration code.

Must-have - frontend

Svelte 5 with runes — not Svelte 4 experience with runes added recently. Much of the work is new components in runes plus converting ontount/onDestroy to Seffect.

React + TypeScript - our second application's frontend. This person moves between both codebases weekly.

Comfortable owning Ul decisions on an authoring/design surface, not just CRUD screens.

Must-have - review and communication

Has been a regular reviewer on someone else's pull requests, not only an author. We will ask for specifics: what they look for, and an example of a review where they caught something real.

Written English strong enough to review code in it and to take a loosely specified issue - ask two or three sharp clarifying questions, then proceed - rather than requiring file-and-line-level instructions.

Writes PR descriptions that explain why, not only what changed.

Request: please put forward people from your client-facing tier - the ones you would put on a call with a US customer.

Nice to Have

Prior work on a design/authoring Ul (canvas, node graph, form builder)

Experience maintaining a large TypeScript API client or shared type layer

Accessibility awareness

Experience in global, multi-time-zone remote teams

4. Working Model

Remote 100%.

Working hours aligned with Canada EST

5. Contract & Interview Process

Contractor position – starts with a 2-week trial, followed by rolling 3-month contracts upon successful completion

Interview process:

Round 1 – English test with team (10m)

Round 2 – Technical + Culture Fit interviews with the Canadian client (60m)

6. Benefits

Competitive senior-level compensation.

High ownership and real technical influence over a core product

Opportunity to work on complex, high-performance apps in the crypto trading space

Global, remote-first team with strong engineering culture

Fast-moving environment where your decisions directly impact users pact users