Senior Software Developer - North York

We are seeking a highly accomplished Senior Software Developer with master-level expertise in multi-tier enterprise systems and open-standard technologies to lead full-stack development, systems analysis, and application integration initiatives. In this role, you will take technical ownership of translating complex business requirements into scalable, robust backend services and interactive user interfaces. Operating across hybrid environments that merge legacy mainframes with modern cloud-adjacent architectures, you will direct solution designs, manage deployment pipelines, and provide strategic technical leadership to ensure absolute performance and platform alignment.

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

Hours: 7.25 hours per day between 8:00 AM and 5:00 PM

Duration: 12-month contract.

• Expansive Technical Domain Scope:
  Master a highly diverse technology ecosystem spanning core legacy mainframe systems, open-source Java environments, and contemporary REST/JSON endpoints.
• Architectural Blueprint Authority:
  Command absolute design and modeling ownership, driving the creation of conceptual, logical, and physical blueprints from inception to release.
• High-Impact Technical Mentorship:
  Lead multidisciplinary IT project delivery team, guiding development practices, quality gates, and code standards.
• Predictable, Highly Collaborative Cadence:
  Structured, fully onsite 12-month engagement optimizing synergy, rapid project gating reviews, and immediate operational impact.

• Lead full‑stack enterprise engineering:
  End‑to‑end analysis, design, coding, and system integration of complex multi‑tier applications across web, desktop, mobile, and legacy mainframe platforms.
• Architect, build, and optimize backend integration layers using JEE, EJB, JNDI, JDBC, JMS, Struts, Web Sphere, Web Logic, Tomcat, and Apache.
• Design and deploy decoupled, secure RESTful and SOAP/WSDL-based Web Services, managing high‑volume enterprise transactions with JSON and XML messaging schemas.
• Design relational data layers and write highly optimized PL/SQL logic, stored procedures, and triggers in Oracle.
• Provide technical oversight and mentorship to analysts, developers, and testers – overseeing estimation, task allocation, and end‑to‑end delivery.
• Author detailed technical documentation, user guides, and architecture deliverables covering conceptual, logical, and physical system states using CASE tools such as MS Visio and Power Designer.
• Implement secure interaction boundaries, managing integrations with identity grids, cryptographic structures, and network controls (LDAP, PKI, VPN).
• Act as principal triage authority for Tier‑3 troubleshooting and bug isolation, deep‑dive debugging, code refactoring, and performance optimization.
• Develop rigorous unit and integration testing scripts, collaborating with QA automation squads for validation paths, stress testing, and vulnerability auditing.
• Navigate applications through corporate technology checkpoints, ensuring designs meet enterprise security, user privacy, and digital accessibility directives.
• Formulate knowledge‑transfer checklists and lead walkthroughs to transition codebases to internal operational staff.

• 10+ years of progressive experience designing, architecting, and developing complex IT solutions in multi‑platform enterprise landscapes (Strictly Required).
• Extensive hands‑on experience with JEE ecosystem: JSP/Servlets, EJB, JNDI, JDBC, JMS, Struts (Strictly Required).
• Expert command of building, testing, and documenting REST and SOAP‑based Web Services with JSON/XML, Swagger, or Postman (Strictly Required).
• Proven experience executing relational database analysis, logical mapping, and PL/SQL development within Oracle RDBMS architectures (Strictly Required).
• Background configuring, monitoring, and maintaining enterprise web servers:
  Web Sphere, Web Logic, Tomcat, Apache, Sun Solaris or Windows Server hosts (Strictly Required).
• 10+ years of proven expertise in isolating multi‑component software errors, rewriting legacy modules, and running performance optimizations (Strictly Required).
• Strong background Dev‑Ops using CASE platforms…