About the Role Idea Theorem is looking for a Senior Application/Software Architect to join a two-year engagement supporting a federal government client on the modernization of mission-critical legacy applications. You'll act as the architectural authority for a portfolio of archival systems built on PHP, C, and early JavaScript technologies dating back to the late 1990s — leading the assessment, stabilization, and modernization roadmap that will guide these systems toward secure, supportable, and sustainable platforms. This is a hands-on architecture leadership role: you'll assess current-state systems, define target-state architectures, produce migration roadmaps, and provide ongoing technical governance as implementation teams execute the modernization. What You'll Do Conduct architecture assessments of legacy applications, including PHP and C-based modules Analyze recurring incidents and operational issues to identify underlying architectural root causes Identify, prioritize, and document technical debt across the application portfolio Define target-state architectures and modernization/migration strategies (including PHP 5.5 → PHP 7/8 and platform upgrades) Lead the redesign of an integration layer connecting core content and enterprise management systems Guide front-end modernization planning for legacy JavaScript-based interfaces Establish architecture standards, design principles, and governance practices Produce architecture decision records, technical specifications, and modernization roadmaps Provide technical leadership, mentoring, and knowledge transfer to internal teams Participate in architecture review boards and provide expert guidance to stakeholders What We're Looking For 10+ years of experience defining, designing, and modernizing application architectures for PHP-based web applications and API solutions (5 years is an absolute minimum; candidates with 10+ years are strongly preferred) 5+ years of experience defining architecture, technical frameworks, and integration patterns for enterprise applications using PHP and/or C/C++ 5+ years of experience designing architectures involving integration with relational databases (Microsoft SQL Server and/or Oracle) A degree or diploma in IM/IT, Computer Science, Software Engineering, or a related field from a recognized Canadian institution is strongly preferred (this is the highest-scoring profile for this engagement) Candidates with a non-IT degree/diploma plus 15+ years of IT experience and relevant certifications, or 20+ years of IT experience, will also be considered — note that a completed post-secondary degree/diploma (IT-related or not) is required in all cases Demonstrated experience working with legacy/long-running systems carrying accumulated technical debt Strong track record of translating legacy system knowledge into clear modernization strategies and documentation Comfortable acting as the architectural authority on a project, including technical governance and stakeholder communication Nice to Have Prior experience with government or public sector clients Experience with legacy C/C++ to C++/.NET migration Familiarity with WCAG 2.1 AA accessibility standards Bilingual (English/French) communication skills Details Location: Remote within Canada, with occasional flexibility for on-site work in the National Capital Region (Gatineau, QC) if needed — no fixed on-site attendance requirement Duration: ~2-year engagement Language: English required for all deliverables and communication Security: Candidate must be eligible to obtain government security screening (Reliability Status) for this engagement How to Apply Interested candidates should submit their resume, along with a brief summary of relevant legacy PHP/C/C++ architecture project experience at ndevi@ideatheorem.com.