Senior Engineer (Senior Full Stack Engineer)
Contract
Location: Mexico, Canada

Role Overview

We are looking for a Senior Full Stack Engineer with strong hands-on expertise in React, Node.js, and SQL who can take end-to-end technical ownership of an application.

The ideal candidate should be capable of looking beyond individual modules or development tasks and understanding the application as a whole—including frontend, backend, APIs, database, integrations, deployment, performance, and production support. The role requires a combination of hands-on development, technical ownership, problem-solving, and team guidance.

Experience

1. 6+ years of software development experience, preferably in full-stack application development.
2. Strong hands-on experience with React, Node.js, JavaScript/TypeScript, and SQL.
3. Experience owning or playing a key technical role in medium-to-large applications.
4. Experience across the complete SDLC: requirements, design, development, testing, deployment, and production support.
5. Experience troubleshooting complex issues across frontend, backend, database, and integration layers.
6. Experience conducting code reviews and mentoring/guiding other engineers.

Must-Have Skills

• React: Components, Hooks, state management, routing, reusable UI design, API integration, and frontend performance.
• Node.js: Backend/service development, REST APIs, asynchronous programming, authentication/authorization, error handling, and logging.
• SQL: Strong query-writing skills, relational database design, indexing, query optimization, and performance troubleshooting.
• Strong proficiency in JavaScript and/or TypeScript.
• Strong understanding of REST APIs, system integrations, and application architecture.
• Knowledge of software design principles, coding standards, and design patterns.
• Strong debugging, analytical, and problem-solving skills.
• Ability to understand an application end to end and assess the impact of changes across the system.
• Strong communication and collaboration skills.

Good-to-Have Skills

• Experience with AWS, Azure, or GCP.
• Knowledge of CI/CD pipelines and automated deployment practices.
• Experience with unit, integration, and automated testing.
• Exposure to microservices and distributed architectures.
• Knowledge of application security and secure coding practices.
• Experience with monitoring, logging, and observability tools.
• Experience modernizing legacy applications and reducing technical debt.
• Familiarity with Agile/Scrum development methodologies.

Responsibilities

• Take end-to-end technical ownership of the application across React frontend, Node.js backend, SQL database, APIs, and integrations.
• Design, develop, enhance, and maintain scalable and reliable application solutions.
• Translate business requirements into appropriate technical designs and implementations.
• Make technical decisions considering scalability, performance, security, maintainability, and reliability.
• Actively contribute to development and handle technically complex implementation tasks.
• Review code and designs to ensure engineering quality and adherence to standards.
• Guide and mentor developers on implementation approaches and engineering best practices.
• Identify and address technical debt, performance bottlenecks, architectural gaps, and security concerns.
• Troubleshoot complex application and production issues and drive root-cause resolution.
• Collaborate with Product, QA, DevOps, Architecture, and other stakeholders throughout the delivery lifecycle.
• Ensure appropriate testing, monitoring, logging, documentation, and production readiness.
• Continuously improve the overall quality, performance, stability, and maintainability of the application.

Key Expectation: This is a hands-on senior engineering role with application-level ownership. The candidate should be able to understand the complete application, independently drive technical solutions, contribute to coding, guide the development team, and ensure the long-term technical health of the application.