senior software developer - api.

We are seeking an experienced Senior Software Developer - API with 8+ years of expertise to drive the design, development, and deployment of scalable, high-performance API solutions and microservices. In this role, you will take technical ownership over converting functional specifications into secure, decoupled, and event-driven applications. Operating across Java, Spring Boot, and cloud environments, you will architect RESTful web services, engineer message-oriented integration pathways, design relational database schemas, and enforce robust security protocols to support critical enterprise platforms.

Location: Toronto, ON (Fully Onsite – 5 days/week required)

Duration: 12-month contract.

Advantages
Enterprise API Ownership: Command full design and execution authority over modern, decoupled Spring Boot microservices.

Cloud & Event-Driven Stack: Architect solutions leveraging Azure Services, Azure Event Hubs, and containerized Kubernetes environments.

Deep Integration Exposure: Solve complex data transformation and messaging challenges using advanced enterprise integration patterns.

Collaborative Onsite Culture: Drive high-impact engineering execution alongside an experienced development squad in a 5-day onsite setting.

Responsibilities
REST API & Integration Engineering: Design, build, consume, and document clean, secure RESTful APIs and integration solutions using Java, Spring Boot, and Spring Integration.

Microservices & Event-Driven Architecture: Architect modular, decoupled microservices and event-driven architectures using Azure Services, Azure Service Bus, and messaging queues for asynchronous data processing.

Data Transformation & Mapping: Map, normalize, and transform complex data structures across JSON, XML, and CSV formats utilizing Spring Integration tools, XSLT, and XPath.

Database Design & Query Optimization: Design efficient relational database schemas and write complex SQL queries using SQL Server or Oracle databases.

Security & Authentication Governance: Secure API endpoints and communication pathways implementing OAuth2, JWT, SAML, input validation, and OWASP security standards.

Testing & Automated Validation: Develop comprehensive automated unit and API test suites using JUnit, Mockito, or Test Containers to ensure code reliability and prevent regressions.

Containerization & CI/CD Deployment: Package applications using Docker, docker-compose, and Kubernetes manifests for smooth cloud deployment and continuous delivery pipelines.

Observability & Monitoring: Integrate operational logging and telemetry frameworks (ELK stack, Splunk, Prometheus, Grafana) to ensure real-time system visibility.

Technical Mentorship & Code Reviews: Conduct regular code reviews, enforce design best practices, and mentor junior developers on the team.

Operational & On-Call Support: Assist with troubleshooting production issues, perform root-cause debugging, and participate in technical support rotas.

Qualifications
REST API & Integration Seniority: Extensive experience designing, building, consuming, and documenting REST APIs and integration solutions using Spring Integration (Strictly Required).

Microservices & Messaging Expertise: In-depth knowledge of microservice architecture and hands-on experience building scalable systems with Azure Services, message queues, event-driven architecture, and asynchronous multi-threading (Strictly Required).

Relational Database Command: Strong SQL proficiency and hands-on experience working with relational databases such as SQL Server or Oracle (Strictly Required).

Security & Token Protocols: Knowledge of security integration using OAuth2, JWT, SAML, and related authentication and authorization technologies (Strictly Required).

Data Transformation & Formats: Proven capability handling data transformation, mapping, and normalization across JSON, XML, and CSV formats within a Spring Integration framework.

Core Java Ecosystem Depth: 8+ years of hands-on software development experience with modern Java features, object-oriented programming, and Spring Boot.

Containerization & Testing Tooling: Practical experience with Docker, Kubernetes, and automated testing frameworks (JUnit/Mockito).

Soft Skills: Outstanding analytical reasoning, technical documentation abilities, and communication skills to collaborate effectively with cross-functional technical teams.

Summary
If you're interested in the "Senior Software Developer - API" role based in Toronto, we encourage you to apply online at
Only qualified candidates will be contacted for the next steps. We look forward to hearing from you!

Randstad Canada is committed to fostering a workforce reflective of all peoples of Canada. As a result, we are committed to developing and implementing strategies to increase the equity, diversity and inclusion within the workplace by examining our internal policies, practices, and systems throughout the entire lifecycle of our workforce, including its recruitment, retention and advancement for all employees. In addition to our deep commitment to respecting human rights, we are dedicated to positive actions to affect change to ensure everyone has full participation in the workforce free from any barriers, systemic or otherwise, especially equity-seeking groups who are usually underrepresented in Canada's workforce, including those who identify as women or non-binary/gender non-conforming; Indigenous or Aboriginal Peoples; persons with disabilities (visible or invisible) and; members of visible minorities, racialized groups and the LGBTQ2+ community.

Randstad Canada is committed to creating and maintaining an inclusive and accessible workplace for all its candidates and employees by supporting their accessibility and accommodation needs throughout the employment lifecycle. We ask that all job applications please identify any accommodation requirements by sending an email to View email address on randstad.com to ensure their ability to fully participate in the interview process.

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