CodeSphere — LMS & Training Platform

Making payment enrollment bulletproof was the most critical challenge. Paystack provides a browser callback URL, but browsers can close before the callback fires — leaving a completed payment with no enrollment. I solved this by building a parallel Paystack webhook handler that activates the enrollment from Paystack's server regardless of what happens on the client, and by de-duplicating both handlers so a double-fire never creates two enrollments.

The quiz-to-certificate pipeline required careful eligibility logic. A certificate should only generate when the trainee has completed every lesson AND passed every quiz above the course's configured pass percentage. I built the eligibility check across LessonProgressModel and QuizAttemptModel before passing control to DomPDF, which renders an HTML certificate template to a downloadable PDF stored on the server with a unique certificate number that can be verified publicly without a login.

The scholarship workflow introduced a three-way enrollment type problem: paid, free, and scholarship all result in an enrollment row, but they must be tracked and displayed differently. I added an enrollment_type enum and scholarship-specific columns (scholarship_by, scholarship_note, scholarship_granted_at) to the enrollments table, and routed all three paths through a shared EmailService helper that selects the correct email template per type — keeping controller logic clean and email formatting consistent.

Building SEO into a CodeIgniter 4 project with no built-in SEO package required writing a custom seo_helper that generates JSON-LD Course schema, Organisation schema, and Breadcrumb schema as inline script blocks, alongside Open Graph and Twitter Card meta tags, from a single function call per view. The SitemapController dynamically queries published courses and categories and outputs a valid XML sitemap, keeping search engine coverage automatic as new courses are published.