Role: Senior Full Stack Engineer

Location: Toronto, ON

Work Arrangement: Onsite

Experience: 10+ Years

Role Summary

We are seeking a Senior Full Stack Engineer with robust hands-on experience in Java, Spring Boot, REST APIs, unit testing, TDD, and modern software engineering practices. The ideal candidate will have a strong foundation in Core Java, a strong focus on code quality and secure development, and experience building scalable, maintainable applications.

Experience with Node.js and modern UI technologies such as React or Angular is an added advantage.

Key Responsibilities

- Design, develop, test, and maintain high-quality Java applications and services using clean code principles, SOLID principles, and established design patterns.
- Build modular, reusable, scalable, and testable RESTful APIs and microservices using Java and Spring/Spring Boot.
- Apply strong Core Java concepts, including:
- Collections
- Generics
- Streams and Lambdas
- Concurrency and Multithreading
- Exception Handling
- JVM Memory Management
- Develop comprehensive and meaningful unit tests using JUnit and Mockito.
- Apply Test-Driven Development (TDD) and continuous testing practices throughout the development lifecycle.
- Implement secure coding practices and apply security-by-design principles, including awareness of OWASP Top 10.
- Conduct code reviews, pair programming, refactoring, and other activities to improve code quality and maintainability.
- Refactor existing codebases to reduce technical debt and improve readability, performance, scalability, and testability.
- Integrate automated testing, static code analysis, security scanning, and quality gates into CI/CD pipelines.




- Use tools such as SonarQube and JaCoCo to monitor and improve code quality and test coverage.
- Use Maven or Gradle for build and dependency management and Git/Bitbucket for source control.
- Diagnose and resolve complex technical, performance, security, and reliability issues.
- Collaborate with architects, business/application analysts, QA, operations, and other cross-functional teams in an Agile environment.
- Document technical solutions, development standards, and implementation details.
- Stay current with emerging development technologies, including AI-assisted development and developer experience platforms, and evaluate opportunities to improve engineering productivity and quality.

Mandatory Skills

- 5+ years of software development experience, with strong hands-on experience in Java.
- Strong expertise in Core Java, including collections, concurrency/multithreading, generics, streams, lambdas, exception handling, and JVM memory management.
- Strong hands-on experience with JUnit and Mockito.
- Solid understanding and practical experience with TDD, test automation, and continuous testing.
- Strong knowledge of Clean Code, SOLID principles, and design patterns.
- Hands-on experience developing RESTful APIs and microservices.
- Strong experience with Spring/Spring Boot.
- Knowledge of secure coding practices and application security fundamentals, including OWASP Top 10.
- Experience with SonarQube, JaCoCo,



or similar code-quality and code-coverage tools.
- Experience with Maven or Gradle.
- Strong experience with Git and Bitbucket or equivalent source-control platforms.
- Experience integrating automated tests, quality checks, and security gates into CI/CD pipelines, preferably Jenkins.
- Strong analytical, troubleshooting, problem-solving, communication, and technical documentation skills.
- Ability to work effectively within a rapid-paced Agile environment.

Preferred / Nice-to-Have Skills

- Hands-on experience with Node.js and backend JavaScript/TypeScript development.
- Experience with modern UI technologies such as:
- React
- Angular
- TypeScript
- JavaScript
- HTML5
- CSS
- Experience using AI-assisted development tools, such as GitHub Copilot.
- Exposure to AI agents or agentic development workflows.
- Experience with Backstage or other developer portal technologies.
- Experience designing and maintaining CI/CD pipelines and developer tooling.
- Experience with Docker and Kubernetes.
- Experience with AWS or other cloud platforms.
- Experience with Jira and Confluence.
- Experience working in Agile/Scrum delivery environments.
- University Degree or College Diploma in Computer Science, Software Engineering, or a related technology discipline.

Core Technology Stack Primary: Java, Spring Boot, REST APIs, Microservices, JUnit, Mockito, TDD

Code Quality & Security: SonarQube, JaCoCo, OWASP, Secure Coding

Build & SCM: Maven/Gradle, Git, Bitbucket

CI/CD: Jenkins, Automated Testing, Quality Gates, Security Scanning

Frontend: React, Angular, TypeScript, JavaScript, HTML5, CSS

Additional: Node.js, Docker, Kubernetes, AWS, Backstage, GitHub Copilot

📌 Senior Full Stack Engineer / Toronto, ON / Onsite / FTE
🏢 AceStack
📍 Toronto