FlowGram is a comprehensive, production-grade visual workflow development framework from ByteDance. The codebase implements two distinct editing paradigms — fixed-layout (automatic positioning with composite nodes like loops, branches) and free-layout (node-position-free with lines) — both built on a shared plugin architecture using inversify for dependency injection. The framework includes a form engine with reactive fields, validation, and effects; a variable engine with AST-based type inference and scoped lifecycle; and a runtime engine capable of executing workflows with executors for LLM, HTTP, code (QuickJS sandbox), and conditions. The repository contains over 40 packages managed via Rush monorepo, encompassing core libraries, plugins (history, minimap, auto-layout, group, snap, clipboard, export), UI material libraries (Semi UI, Ant Design), a CLI tool for scaffolding, multiple demo applications, and comprehensive documentation. The system is actively maintained with regular commits, CI workflows, and E2E tests. Notable technical decisions include a local fork of the use-gesture library for canvas interaction, heavy decorator-based IoC, and support for both React 17 and 18. While the architecture is well-structured and extensible, the codebase shows signs of duplication between fixed and free layouts, numerous demo-specific components, and some deprecated APIs that indicate ongoing refactoring.