Senior Full Stack Engineer

Acestack; Toronto; On-site; CAD 120,000 - 150,000; Full time

Job summary

Acestack in Toronto, ON is seeking a Senior Full Stack Engineer to design, develop, and maintain robust Java applications and services onsite. You will implement unit tests with JUnit/Mockito, embrace TDD and continuous testing, and build RESTful APIs with Spring Boot while ensuring security-by-design across the development lifecycle.

You will collaborate with architects, analysts, operations, and testers in a fast-paced, Agile environment, focusing on code quality, performance, and

Qualifications

• 5+ years of software development experience in Java/NodeJs across the full development life cycle.
• Experience with modern UI technologies (React, Angular, TypeScript, JavaScript, HTML5, CSS).
• Strong command of core Java concepts, including collections, concurrency/multithreading, generics, streams, and JVM memory management.
• Proven experience writing unit tests with JUnit and Mockito; knowledge of TDD and continuous testing.
• Experience building RESTful APIs and microservices with Spring/Spring Boot; security-conscious coding.
• Familiarity with CI/CD pipelines (Jenkins) and code quality tools (SonarQube, JaCoCo).
• Solid knowledge of build tools (Maven, Gradle) and SCM (Git, Bitbucket).
• Excellent problem-solving, communication, and documentation; Agile collaboration.

Responsibilities

• Design, develop, and maintain high-quality Java applications and services.
• Write unit tests with JUnit and Mockito to ensure correctness and reliability.
• Apply TDD and continuous testing to maximize coverage and prevent regressions.
• Build modular, reusable REST APIs and microservices with Spring Boot.
• Embed security-by-design and follow secure coding standards.
• Lead code reviews, pair programming, and coding standard adherence.
• Refactor to reduce technical debt while improving readability, performance, and testability.
• Apply core Java concepts to build robust solutions; optimize JVM memory usage.
• Integrate automated tests, static analysis, and security gates into CI/CD pipelines.
• Collaborate with architects, analysts, operations, and QA to deliver reliable solutions.

Skills

Java

NodeJs

React

Angular

TypeScript

JavaScript

HTML5

CSS

Core Java

JVM memory management

JUnit

Mockito

TDD

CI/CD

SOLID principles

Security

Spring Boot

REST APIs

Maven

Gradle

Git

Bitbucket

Jenkins

Agile

AI tools

Copilot

Backstage

Docker

Kubernetes

AWS

Jira

Confluence

Education

University Degree in Computer Science

College Diploma in Computer Science

Tools

Spring Boot

JMeter

Job description

Senior Full Stack Engineer

Location: Toronto, ON
Job Type: Full Time
Work Model: Onsite

Roles and Responsibilities

• Design, develop, and maintain high-quality, maintainable Java applications and services using clean code principles and established design patterns.
• Write comprehensive, meaningful unit tests using JUnit and Mockito to ensure code correctness, reliability, and long-term maintainability.
• Apply test-driven development (TDD) and continuous testing practices to drive design, maximize coverage, and prevent regressions.
• Build modular, reusable, and testable applications and APIs (REST web services) in Java.
• Embed security-by-design throughout the development life cycle, following secure coding standards and addressing vulnerabilities early.
• Champion code quality through thorough code reviews, pair programming, and adherence to coding standards and best practices.
• Refactor and improve existing codebases to reduce technical debt and enhance readability, performance, and testability.
• Apply core Java concepts-collections, concurrency and multithreading, generics, streams, exception handling, and JVM memory management-to build robust solutions.
• Integrate automated unit testing, static code analysis, security scanning, and quality gates into CI/CD pipelines.
• Use tools such as SonarQube and JaCoCo to measure, enforce, and continuously improve code quality and test coverage.
• Collaborate with architects, business and application analysts, operations teams, and testing specialists to deliver reliable, secure, high-quality solutions.
• Diagnose, troubleshoot, and resolve complex technical, performance, security, and reliability issues.
• Stay current with emerging technologies, including AI-assisted development and developer experience platforms, and evaluate how they can improve quality and productivity.

Skills Required

• 5+ years of software development experience in Java / NodeJs, spanning the full application development life cycle.
• Experience with modern UI technologies (for example, React, Angular, TypeScript, JavaScript, HTML5, CSS) is preferred.
• Strong command of core Java concepts, including collections, concurrency/multithreading, generics, streams, lambdas, exception handling, and JVM memory management.
• Proven, hands-on experience writing effective unit tests with JUnit and mocking frameworks such as Mockito.
• Solid understanding of test-driven development (TDD), test automation, and continuous testing practices.
• Deep commitment to code quality, clean code, SOLID principles, and design patterns.
• Working knowledge of secure coding practices and application security fundamentals (for example, the OWASP Top 10).
• Experience building RESTful APIs and microservices using frameworks such as Spring / Spring Boot.
• Experience with static code analysis, code coverage, and security scanning tools such as SonarQube and JaCoCo.
• Experience with build tools such as Maven or Gradle and source code management tools such as Git and Bitbucket.
• Experience integrating automated tests, quality checks, and security gates into CI/CD pipelines (for example, Jenkins).
• Strong analytical, problem-solving, communication, and technical documentation skills.
• Ability to work effectively in a fast-paced, cross-functional Agile environment.

Nice to Have (Added Advantage)

• Experience using AI-assisted development tools (for example, GitHub Copilot) to accelerate coding and testing.
• Experience working with AI agents or agentic development workflows.
• Experience with backend API technologies such as Node.js is preferred.
• Experience with Backstage and related developer portal technologies.
• Experience building and maintaining CI/CD pipelines and related tooling.
• Experience with containerization and orchestration technologies such as Docker and Kubernetes.
• Experience with cloud platforms such as AWS.
• Experience with Jira, Confluence, and Agile delivery practices.
• University Degree or College Diploma in Computer Science or a related technology field.