Java Developer (React)

Collabera; Toronto; Hybrid; CAD 110,000 - 152,000; Part time

Job summary

Collabera is seeking a Senior Full Stack Engineer to help decompose a legacy monolithic app into cloud-native microservices. You will work on a backend-heavy role (80%) with Java and Spring Boot while contributing to React UI improvements.

The position focuses on modernizing a mission-critical platform used in Public Markets. Hybrid, Toronto-based, with a 6-month contract plus extension potential.

Qualifications

• Senior Java development with deep Spring Boot expertise.
• Experience building and refactoring microservices architectures.
• Strong background in distributed, high-performance systems.
• Frontend contribution in React and cloud native AWS.
• Capital Markets or financial services domain experience is preferred.

Responsibilities

• Refactor a large monolithic application into microservices.
• Design, develop and maintain backend services with Java and Spring Boot.
• Contribute to architecture discussions and technical design decisions.
• Develop and deploy cloud-native applications in AWS.
• Build and enhance React-based UI components.
• Collaborate with analysts and stakeholders across Capital Markets.
• Ensure performance, security, resilience and scalability.
• Participate in code reviews and engineering best practices.

Skills

Java development

Spring Boot

Microservices

Distributed systems

React

AWS

Capital Markets

Problem solving

Communication

Independent work

Tools

Mockito

Testing frameworks

Job description

Type: 6-month contract + opportunity to extend

Location: Downtown Toronto, ON - Hybrid (4 day/week on-site)

Why Is This Role Open?

Client is executing a large-scale transformation to refactor a legacy monolithic application into a microservices-based architecture.

The Senior Full Stack Engineer will join a Capital Markets engineering team responsible for modernizing and rebuilding a mission-critical platform used across Public Markets. This is primarily a backend-focused role (approximately 80% backend / 20% frontend), requiring deep expertise in Java development while also contributing to React-based UI enhancements.

The successful candidate will play a key role in decomposing a legacy monolithic application into cloud-native microservices while supporting ongoing user interface enhancements for portfolio management users.

Day-to-Day Responsibilities

• Refactor and decompose a large monolithic application into microservices.
• Design, develop, and maintain backend services using Java and Spring Boot.
• Contribute to architecture discussions, service boundaries, and technical design decisions.
• Develop and deploy cloud-native applications in AWS.
• Build and enhance React-based UI components
• Collaborate with developers, business analysts, and Capital Markets stakeholders
• Ensure systems are highly performant, secure, resilient, and scalable.
• Participate in code reviews and engineering best practices.

Must-Have Skills

• 10+ years of enterprise Java development experience. (80%)
• Advanced Spring Boot expertise.
• Proven experience building and refactoring microservices architectures.
• Experience designing and developing distributed, high-performance systems.

Frontend Development

• Comfortable contributing to frontend features and UI enhancements
• Cloud- AWS experience (preferred)

Capital Markets Experience (if they don't have capital markets, should at least come from financial services/ retail banking).

• Public Markets experience.
• FX experience.
• Understanding of front-office trading workflows.

Soft Skills

• Strong analytical and problem-solving abilities.
• Ability to work independently in a fast-paced engineering environment.
• Strong communication and collaboration skills.

Nice-to-Haves

• Experience with portfolio management or trading platforms.
• Mockito and automated testing frameworks.
• Exposure to AI/ML concepts.
• Experience working in highly regulated financial environments.

We may use AI-enabled and/or automated tools to support parts of our recruitment process, including application screening, interview scheduling, and candidate communications. These tools are used to enhance consistency and efficiency. All hiring decisions involve human review and are not based solely on automated processing.

The Company offers a total rewards package in accordance with all applicable federal, provincial, and local laws and requirements. Benefit eligibility and offerings vary based on role, employment status, and work location. For contractor positions, benefits are limited to those entitlements and protections required by applicable law, which may include (as applicable) vacation pay, public holidays, leaves of absence, and other legally mandated benefits or payments.