Totum is a self-hosted, low-code/no-code application framework built on PHP 8.3 and PostgreSQL. It functions as a dynamic database and spreadsheet hybrid, allowing users to define data structures (tables, fields) via JSON configuration and implement business logic using a proprietary DSL ('Totum-code'). The system features a modular architecture with a CLI management tool (`bin/totum`), a web-based UI (`http/index.php`), and extensive role-based access control (RBAC). It supports multi-tenancy via schema mapping, external service integration (PDF, Excel, AI), and automated installation via Ansible playbooks for Ubuntu environments. The core logic relies heavily on traits for shared functionality and abstract base classes for table and field handling, creating a flexible but complex codebase. The application is designed for rapid business application construction (CRM, ERP, custom tools) without requiring traditional coding. It stores schema definitions and field configurations in PostgreSQL JSONB columns, enabling runtime structure modification. The calculation engine (`Calculate.php`) parses and executes custom code strings for data validation, formatting, and cross-table logic. While the architecture is robust for its intended purpose, it exhibits signs of technical debt including monolithic frontend JavaScript (`main.js`), hardcoded paths in installation scripts, and reliance on legacy libraries (Chart.js v2, jQuery). The codebase demonstrates significant craftsmanship in its dynamic table engine and calculation DSL, but maintenance requires careful handling of the custom parsing logic and schema migrations.