senior software developer - back end.

We are seeking a highly accomplished Senior Software Developer - Back End to drive the technical design, development, and integration of robust server-side logic for enterprise applications. In this role, you will take technical ownership of managing high-performance data interchanges between backend architectures and front-end users. Working natively within the software development lifecycle, you will translate complex systems specifications into secure, data-driven applications, optimize data storage environments, and implement reliable communication protocols to support modern, multi-client transactional workflows.

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

Hours: Standard operational hours between 8:00 AM and 5:00 PM

Duration: 6-month contract.

Advantages
Core API Framework Authority: Own the end-to-end design of scalable RESTful web services handling complex multi-client transactions.

Hardened Security Architecture Exposure: Maximize your portfolio depth by deploying enterprise identity gates using modern JWT and OAuth 2.0 protocols.

High-Volume Relational Engineering: Drive complex data mapping and query optimizations across heavy Oracle/SQL database infrastructures.

Predictable, Impact-Driven Workspace: Benefit from a highly structured, fully onsite contract delivery model built for real-time team collaboration.

Responsibilities
Server-Side Application Engineering: Architect, design, and code complex backend application logic, ensuring high performance, low-latency responsiveness, and seamless data structures.

API Architecture & Integration: Design and deploy decoupled, secure RestAPIs and RESTful Web Services to facilitate reliable cross-platform communications.

Security & Protocol Hardening: Implement industry-standard authorization and authentication rules using security gateways and protocols, explicitly managing JWT, OAuth 2.0, and SSL Certificates.

Database Programming & Tuning: Program data-driven modules and optimize data access structures within relational database layers using Oracle and SQL Server systems.

Technical Troubleshooting & Bug Triage: Resolve deep-seated technical incidents, diagnose application bottlenecks, and fix defects through comprehensive debugging, refactoring, and performance optimization.

Full-Lifecycle Unit Testing: Author detailed programming specifications, compile complex source codes, and write automated unit test beds to validate code integrity prior to release phases.

Architectural Blueprint Walkthroughs: Document structural requirements and conduct solution design walkthroughs with multidisciplinary engineering squads to verify system feasibility.

Front-End Element Synthesis: Coordinate with front-end engineering pods to seamlessly integrate customer-facing components into core business logic and database registries.

Post-Implementation Deployment Support: Package application components, modify product installation scripts, and deliver tier-3 post-implementation maintenance support.

Qualifications
Enterprise Software Engineering Seniority: 10+ years of progressive professional experience serving as a designer and developer building large-scale, multi-client web applications (Strictly Required).

Master-Level Java & Database Stack Depth: 10+ years of dedicated, hands-on working experience executing Java development paired natively with Oracle or SQL database environments (Strictly Required).

Decoupled Web Services Specialization: 5+ years of direct technical experience designing, building, and maintaining RestAPIs and RESTful Web Services (Strictly Required).

Cryptographic & Identity Governance Literacy: Referenceable practical knowledge of secure integration components, specifically JWT, OAuth 2.0, and SSL Certificate configurations (Strictly Required).

Structured Methodologies Mastery: Deep understanding of full-lifecycle development methodologies, object-oriented programming concepts, and contemporary deployment workflows.

System Triage & Documentation Prowess: Proven capability to troubleshoot multi-component software errors, modify configuration scripts, and write comprehensive system and user guides.

Soft Skills: Outstanding analytical reasoning, collaborative problem-solving, and communication mechanics, with an established history of aligning code deliverables with strict project deadlines.

Preferred Assets:
Familiarity with Rapid Application Development (RAD) methodologies and middleware gateway configurations.

Basic working knowledge of data protection practices and regional digital accessibility standards (such as AODA).

Summary
If you're interested in the "Senior Software Developer - Back End" 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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