Senior Full-Stack Developer Toronto

Appnovation is a global, full-service digital partner that combines Strategy, Experience & Design, Engineering and Managed Services. We build digital solutions that deliver real impact today and serve as foundations for future growth. Bold ambition. Practical action. Endless possibilities.

ROLE OVERVIEW: As a Full-Stack Developer, you will architect and build custom web applications across multiple client engagements, owning both the backend API layer and the frontend. A defining aspect of this role is working with AI as a logic layer within applications: integrating LLM APIs for validation, decision-making, classification, and content generation. You make strong technical decisions around authentication, security, state management, and performance, and you bring cloud engineering awareness for edge computing, CDN delivery, and serverless environments. This is not a traditional manual coding role. You orchestrate AI development tools, primarily Claude Code, through strategic prompting and rigorous review, taking full ownership of what ships.

RESPONSIBILITIES: Your key responsibilities will include:

Architect and build custom web applications using Node.js (Nest.js, Express, Hono), Python (FastAPI, Flask), and Next.js/React.

Design and build RESTful and/or GraphQL APIs that serve multiple frontends and integrate with third-party services.

Integrate AI and LLM APIs as a core logic layer, building intelligent features such as validation, classification, content generation, and decision support.

Implement authentication, authorisation (JWT, OAuth, RBAC), and security across applications.

Design and manage database layers (PostgreSQL, MongoDB, cloud-managed equivalents), including schema design, migrations, and query optimisation.

Architect with cloud-native patterns: edge functions, CDN configuration, serverless deployments, and caching strategies.

Write and maintain automated tests across the full stack: unit (Vitest/Jest), API/integration, component (React Testing Library), and E2E (Playwright/Cypress).

Orchestrate AI development tools (Claude Code) through strategic prompting, ensuring high-quality, production-ready output.

EXPERIENCE: The ideal candidate will have:

Strong backend proficiency across Node.js (Nest.js, Express, Hono) and Python (FastAPI, Flask), with TypeScript and Python as working languages.

Strong Next.js and React experience.

Experience integrating AI/LLM APIs as an application logic layer: validation, classification, content generation, and decision-making within business workflows.

Database design and management: PostgreSQL, MongoDB, cloud-managed services (Cloud SQL, RDS, ApsaraDB).

Authentication and authorisation patterns (JWT, OAuth, RBAC) and API security.

Cloud engineering: edge functions, CDN configuration, serverless architecture, container orchestration.

Full-stack test automation: unit, API/integration, component, and E2E testing.

Performance optimisation: caching, query optimisation, code splitting, monitoring.

REST and/or GraphQL API design.

Demonstrated ability to orchestrate AI development tools through strategic prompting and quality oversight.

TECHNOLOGIES: Deep understanding of the following technologies is essential:

Next.js, React, Tailwind CSS.

PostgreSQL, MongoDB, cloud-managed database services.

Cloud and edge: Alibaba Cloud, GCP, AWS, Cloudflare Workers, Vercel Edge, Lambda.

AI/LLM API integration and orchestration.

Testing: Vitest/Jest, React Testing Library, Playwright/Cypress, API testing.

PREFERRED QUALIFICATIONS:

Experience in a consulting or agency environment across multiple concurrent client engagements.

Apollo GraphQL Server for federated or schema-first APIs.

Multi-model AI strategies (routing between LLMs based on task requirements).

Graph databases (Neo4j) or vector databases (pgvector, Pinecone).

Infrastructure as Code (Terraform, Pulumi).

WHO YOU ARE: You are a full-stack developer who takes ownership of the complete application, from API design and database schema through to the frontend. You treat security, performance, and data integrity as first-class concerns. You are comfortable working with AI as a logic layer, and you understand cloud-native architecture well enough to make informed decisions about edge computing, caching, and deployment. You thrive in a consulting environment, adapting to new domains and communicating clearly with technical teams and client stakeholders.

WHAT APPNOVATION HAS TO OFFER:

Challenging and rewarding work with real impact

Direct Access to Cutting-Edge AI Platforms

Diverse and Inclusive Culture

Growth opportunities for personal and professional development

A collaborative and innovative work environment where your ideas are valued

Exposure to exciting projects and high-profile clients

Supportive work environment with access to company leaders

At Appnovation, we recognize that diverse teams are the strongest teams. Diversity, Equity & Inclusion is not only something that we embrace - we celebrate it! We are proud to be an Equal Opportunity Employer and we encourage applicants from all backgrounds, lived experiences and industries to apply. Come join us at Appnovation, and learn more about how we stay true to our company values as we build better lives through better digital.

Accommodations are available upon request throughout the recruitment process.

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