QST vs. TAO Community Edition vs. TCExam:   Why "Open Source" Should Mean Full Power When choosing an assessment platform, "Open Source" can mean three very different things. For some companies, it’s a marketing lead-magnet designed to funnel you into a paid cloud subscription. For QST, it is a complete, industrial-grade engine provided without restrictions. For TCExam it is a limited feature set and limited scalability. The "Commercial Trap" vs. The "Industrial Tool" vs. The "Limited Edition" Most modern assessment platforms offer a "Community Edition" (CE) that is intentionally limited. They remove high-concurrency support, advanced reporting, or STEM tools to force you into their Enterprise tiers. QST takes the opposite approach. We believe your assessment data and performance shouldn't be held hostage by a subscription model. TCExam locks your questions into their format and offers you no way to download them, although they are your property. Also it is missing the GradeBook that QST has which is so important to see deep analytics of questions and student progress over time. 1. Performance Without the "Paywall" TAO CE:  Lacks the specialized caching and optimization found in their paid "Ignite" or "Enterprise" tiers. Scaling to thousands of users often requires expensive cloud configurations. TCExam: Not built for easy scaling to large testing numbers. QST:  Built on a high-performance, multi-threaded mod_perl, Apache and MySQL architecture. QST is engineered to handle 1,000+ simultaneous test-takers on standard hardware, right out of the box. 2. Native STEM Support (No Plugins Required) TAO CE:  Rendering complex math and chemistry often requires third-party plugins, manual configuration, or paid add-ons. TCexam:  Rendering complex math and chemistry equations not available. Basic latex input. QST:  Features a native VisualLaTeX, MathML, and mhchem editor. Whether you are testing basic math or advanced organic chemistry, the tools are built into the core engine.No need to know latex or tex. 3. Security and Zero-Footprint Deployment TAO CE:  History of security vulnerabilities. TCexam:  History of security vulnerabilities. QST:  Boasts a record of zero security vulnerabilities (CVEs). Single point access, all input sized, sanitized, verified and whitelisted. No API's. No dependencies. Single file - QST.pm to perform a security audit on. Because it is 100% self-hosted and on-premise, you maintain absolute control over your data—qualifies for GDPR, HIPAA, and FERPA compliance. 4. Open Source License TAO CE:   AGPLv3 means you must Contribute any modifications you make back to TAO or purchase a license - Read their fine print. This license is incompatible with many organizations privacy requirements. TCexam   AGPLv3 means you must Contribute any modifications you make back to TAO or purchase a license - Read their fine print. This license is incompatible with many organizations privacy requirements. QST:   GPLv2 only, no need to to contribute your changes. You own your modifications. 5. "Un-Crippled" Features as Standard     While others "nickel and dime" you for features, QST includes the following as standard: QTI, Moodle XML and Word XML compatible (No vendor lock-in) Professional WYSIWYG Question Editor Professional WYSIWYG Visual LaTex Editor Multiple Question Types - 16 Combinations Unique Memory Option - Test a students active recall and retention-key aspects of knowledge Auto marking of Math and Chemistry equations Automated Question Randomization Question Pooling Advanced Gradebook and Reporting Immediate Actionable Detailed Results Multiple Exam Display Options Multiple Exam Results Displays for Students Set the Date/Time Range for the QST to be Available Shuffle Questions for each Student Shuffle Question Answers for each Student Record Mark and Record Highest Mark if Multiple Attempts Allowed Display Correct Answers to Students and Explanations View a students exam as it is being taken Production Grade on Linux, Windows and macOS Industrial grade UI, very intuitive for all users Multi-tenancy Separate Administrators for each Organization Separate Organizational Question Banks Administrators Bulk import Instructors, Students, Classes, Student Photo's Each Instructor has their own Question Bank and Exam/Quiz/Survey Bank Instructors have File Managers - Manage Image File Desriptions for WCAG 2 compliance Instructors Control and Manage their own Assessments Instructors Bulk Import/Export Questions in Multiple Formats Multi-Language - Easily Convert QST Language Strings to your Language Using Your AI RTL for Students One File Update Phone friendly User contributed Docker container install on GitHub Brave AI Comparison Chart Dimension QST TAO CE TCExam Results Management / Analytics ✅ Full GradeBook + per-question stats + CSV/JSON export ❌ Locked to paid tier Basic only Multi-tenancy (orgs/classes/users) ✅ Unlimited orgs, separate admins per org ❌ ❌ Proctoring (XTRASecure, kiosk, SEB) ✅ Built-in Paid add-on ❌ Branching / Skip Logic ✅ ✅ ❌ STEM (MathJax, LaTeX, chemistry) ✅ Visual editor + auto-marking Paid add-on ❌ QTI / Moodle XML / Word XML import ✅ All three QTI only Limited AI-assisted question creation ✅ (via GitHub project) ❌ ❌ Adaptive delivery (random X from bank per student) ✅ ✅ ❌ "Memory" feature (show material once, test recall) ✅ Unique to QST ❌ ❌ PDF export of marked exam with timestamps ✅ Paid ❌ Zero security vulnerabilities (claimed) ✅ Not stated Not stated    The Bottom Line     If you want a "pretty" marketing demo that eventually asks for a credit card, choose TAO CE version. If you want a php app with limited features and lockin choose TCExam. If you want a battle-hardened, high-concurrency engine that respects your budget and your data, QST is the logical choice.