Senior Full-Stack Software Engineer (Python / Django / React / Next.js)

We're a Toronto-based technology startup developing an AI-powered SaaS business management and local services marketplace platform.

Our products include business management, appointment booking, scheduling, customer engagement, location-based discovery, community features, and AI-powered solutions.

Our web platform and iOS and Android mobile applications are already live, serving real businesses and customers.

We are focused on strengthening our existing systems, improving cross-platform functionality and reliability, and rapidly delivering new features.

We are seeking a hands-on Senior Full-Stack Software Engineer with strong backend expertise to take technical ownership of our existing production codebase, improve system architecture, and independently deliver reliable features across our web and mobile platforms.

This is a hands-on engineering role, not a purely managerial, architectural, or advisory position.

• Develop, maintain, and optimize our Python / Django / Django REST Framework backend and PostgreSQL database.
• Design and implement complex business logic, REST APIs, authentication, authorization, and data workflows.
• Build and maintain reliable backend services supporting our web, iOS, and Android applications.
• Review and improve system architecture, database structures, performance, security, and maintainability.
• Plan and execute database migrations with appropriate testing, data integrity checks, and rollback strategies.
• Investigate and resolve complex backend issues, recurring bugs, performance problems, and integration failures.
• Integrate and maintain third-party services, including AI APIs, payment systems, messaging solutions, and notifications.
• Improve production reliability through logging, monitoring, automated testing, and deployment practices.

• Independently deliver complete features across backend, database, APIs, and frontend.
• Develop and maintain web applications using TypeScript, React, and Next.js.
• Implement accurate, responsive frontend UI, including forms, dashboards, calendars, user interactions, and detailed visual refinements.
• Ensure consistent functionality, business logic, data handling, and user permissions across web, iOS, and Android applications.
• Develop, maintain, and troubleshoot API integrations used by mobile applications.
• Collaborate on mobile-related functionality, including authentication, booking workflows, payments, notifications, and account management.
• Diagnose and resolve cross-platform issues involving mobile clients, backend APIs, and database operations.
• Work effectively within an existing codebase, prioritizing practical improvements over unnecessary rewrites.
• Complete assigned features through implementation, self-testing, integration testing, and production verification.

• Review code, identify architectural risks, and provide practical improvements.
• Conduct code reviews and offer technical guidance to other developers.
• Write maintainable code and meaningful automated tests.
• Improve Git workflows, pull request standards, CI/CD practices, and release reliability.
• Identify root causes of production issues and implement lasting fixes.
• Ensure changes to shared APIs and database structures do not unintentionally disrupt web or mobile applications.
• Balance engineering quality, delivery speed, security, and long-term maintainability.

• Work directly with the founder and development team to translate business requirements into technical solutions.
• Proactively identify missing requirements, edge cases, technical dependencies, and potential risks.
• Break down complex features into manageable tasks with realistic timelines.
• Communicate progress, blockers, and technical decisions clearly and concisely.
• Explain technical concepts and trade-offs to nontechnical stakeholders.
• Take ownership of assigned features from planning through delivery and verification.
• Adapt to evolving requirements and priorities in a fast-moving startup environment.

• 6+ years of professional software development experience, including substantial hands-on full-stack development.
• Demonstrated experience independently developing, maintaining, and improving production applications.
• Strong production experience with Python, Django, and Django REST Framework.
• Strong proficiency in TypeScript, React, and Next.js.
• Solid PostgreSQL experience, including data modeling, migrations, transactions, indexing, and query optimization.
• Strong understanding of REST API architecture, authentication, authorization, security, and complex business logic.
• Experience developing and maintaining backend services and APIs consumed by web and mobile applications.
• Understanding of cross-platform integration challenges, including API compatibility, data consistency, authentication, and error handling.
• Ability to independently implement detailed frontend UI, responsive layouts, forms, and user interactions.
• Experience troubleshooting existing production codebases and resolving issues across frontend, backend, database, and API layers.
• Proficiency with Git, GitHub, pull requests, and code review practices.
• Experience writing automated tests using pytest, Jest, or similar frameworks.
• Familiarity with Linux, Docker, cloud deployment, CI/CD, and production troubleshooting.
• Ability to estimate work, prioritize tasks, communicate blockers, and consistently deliver tested, production-ready software.
• Strong analytical thinking, accountability, independent problem-solving, and clear communication skills.

• Hands-on React Native / Expo experience developing or maintaining iOS and Android applications.
• Experience debugging mobile applications and supporting App Store / Google Play releases.
• Experience with mobile push notifications, deep linking, mobile authentication, and device-specific integrations.
• Experience building SaaS platforms, marketplaces, booking systems, CRM applications, or business management software.
• Experience supporting products from MVP through launch and ongoing production use.
• Experience integrating OpenAI APIs, LLM-powered features, AI Agents, or automated workflows.
• Experience with Stripe, Twilio, webhooks, and third-party payment or communication systems.
• Familiarity with GCP, AWS, Redis, Celery, or infrastructure automation.
• Experience handling production database migrations and maintaining data integrity.
• Experience mentoring developers or improving code review and release practices.
• Experience using AI-assisted coding tools effectively while independently reviewing and testing generated code.
• Experience working in early-stage startups or small development teams.
• Ability to communicate in English and Mandarin is an asset.

We value engineers who combine strong technical judgment with efficient, reliable hands-on execution.

The ideal candidate:

• Can quickly understand an unfamiliar production codebase and begin contributing independently.
• Has strong Django/PostgreSQL expertise while remaining comfortable implementing React/Next.js features.
• Understands how backend changes affect web and iOS/Android applications.
• Can diagnose complex issues across multiple systems and identify root causes.
• Delivers complete, tested functionality rather than isolated or partially finished tasks.
• Pays attention to business logic, UI accuracy, data integrity, and user experience.
• Proactively identifies risks and makes practical technical recommendations.
• Communicates clearly without unnecessary technical complexity.
• Supports other developers through constructive technical guidance and code review.
• Can work efficiently in a small team with evolving product requirements.

We value demonstrated technical ability, ownership, and reliable delivery more than job titles alone.

• Meaningful technical ownership of a live SaaS platform and iOS/Android applications.
• Direct involvement in technical decisions and product development.
• Opportunities to work across backend systems, frontend applications, mobile integrations, and AI-powered features.
• Close collaboration with the founder and core engineering team.
• Remote work initially, transitioning to hybrid collaboration in the GTA.
• Professional growth opportunities as the company develops.

Please submit your resume and, where available, your GitHub profile, portfolio, or relevant project links.

In your application, please briefly describe:

• A production application or backend system you personally developed, maintained, or significantly improved.
• Your experience with Django / DRF, PostgreSQL, React, and Next.js.
• Your experience supporting web and iOS/Android applications through shared backend APIs or mobile development.
• A complex technical issue, database migration, or production problem you independently resolved.
• Your experience delivering complete full-stack features, including testing and deployment.
• Your current availability, earliest possible start date, and salary expectations.

Shortlisted candidates will participate in a technical interview and practical engineering assessment covering backend architecture, existing-codebase troubleshooting, full-stack implementation, cross-platform API considerations, testing, and independent delivery.

We are looking for an experienced, hands-on engineer who can contribute immediately and help strengthen the technical foundation of our growing platform.

Company Website: https://cosready.ai

Pay: $80,000.00-$100,000.00 per year

• Profit sharing
• Stock options