Senior Software Developer - API

We are seeking an experienced Senior Software Developer - API to lead the technical design, development, security, and integration of enterprise-scale RESTful web services and API platforms. In this role, you will translate technical system specifications into robust, production-tested applications and microservices. Leveraging deep expertise in Java development, relational databases (Oracle and SQL Server), API management platforms, and modern security protocols (OAuth 2.0, JWT, TLS/SSL), you will build scalable interfaces, implement gateway policies, convert legacy services between SOAP and REST, integrate with core enterprise platforms, and support the full Software Development Life Cycle (SDLC) within an Agile delivery model.

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

Duration: 12-month contract.

Advantages
Long-Term Stability: Secure a comprehensive 12-month contract delivering core enterprise integration modernization.

Modern Integration Scope: Lead hands-on development across RESTful APIs, microservices, and enterprise gateway platforms.

Full-Lifecycle Ownership: Drive solutions from technical specification and API modeling through deployment and performance tuning.

Dedicated Onsite Collaboration: Work directly with multidisciplinary technical squads and solution architects in Toronto.

Responsibilities
Translate functional requirements and technical system specifications into working, scalable, tested, and secure API solutions.

Design, develop, code, and implement RESTful APIs, web services, and microservices using Java and modern integration frameworks.

Develop, configure, and maintain API management solutions and gateways (such as Azure APIM, MuleSoft, Apigee, or IBM API Connect).

Implement API gateway policies, including rate limiting, throttling, caching, custom logging, and request/response transformations.

Secure API endpoints and data transmission utilizing OAuth 2.0, JWT, API keys, mutual TLS, and SSL certificates.

Convert legacy web services from SOAP to REST and vice versa to modernize enterprise integration patterns.

Connect APIs to relational databases (Oracle, SQL Server) and enterprise platforms (including CRM systems, SharePoint, and case management tools).

Author comprehensive API specifications, contracts, and documentation using OpenAPI (Swagger) and YAML standards.

Conduct unit testing, integration testing, code reviews, debugging, and root-cause troubleshooting for production and pre-production issues.

Collaborate closely with cross-functional Agile delivery teams, including business analysts, quality assurance specialists, architects, and product owners.

Facilitate technical design walkthroughs and deliver structured knowledge transfer to team members and operational staff.

Qualifications
Large-Scale Web Application Experience: 10+ years of proven experience designing and developing large-scale, multi-client web applications (Strictly Required).

Java & Relational Database Development: 10+ years of hands-on working experience in Java development integrated with Oracle or SQL Server databases (Strictly Required).

REST API & Web Services: 5+ years of dedicated, hands-on experience designing and implementing RESTful APIs, web services, and enterprise integration patterns (Strictly Required).

API Security & Gateway Protocols: Solid working knowledge of API security standards and protocols, including OAuth 2.0, JWT, and SSL/TLS certificate handling (Strictly Required).

Agile Delivery: Proven experience and solid understanding of Agile development methodologies, sprint ceremonies, and iterative delivery (Strictly Required).

Nice-to-Have Assets:
Prior software development or API engineering experience within a public sector or large enterprise environment.

Hands-on experience with API management and ESB platforms such as Azure APIM, MuleSoft, Apigee, or IBM API Connect/ACE.

Experience with containerization tools (Docker) and CI/CD pipelines.

Understanding of digital accessibility standards (AODA/WCAG) and enterprise architectural governance processes.

Summary
If you're interested in the "Senior Software Developer - API" role based in Toronto, we encourage you to apply online at www.randstad.ca.

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 [email protected] to ensure their ability to fully participate in the interview process.

This posting is for existing and upcoming vacancies.