Codebase overview template
The document every new developer wishes they had on day one.
A codebase overview document gives new developers a mental model of the system before they open a single file. It answers the big questions: what does this do, how is it organized, what technologies are used, and how does data flow through the system.
This template is structured for quick reading. Each section fits on one page or less. The goal is a 15-minute read that saves hours of code exploration.
Project summary
What the project does in 2-3 sentences. Include the primary user, the core value proposition, and the current status.
Example
TaskFlow is a project management tool for small teams. Users create projects, assign tasks, set deadlines, and track progress through a kanban board interface. The application is in production with approximately 5,000 monthly active users.
Architecture diagram
A visual diagram showing the major components and how they connect. Include frontend, backend, database, external services, and infrastructure.
Example
[Browser] -> [Next.js App (Vercel)] -> [Supabase (Postgres + Auth)] -> [Stripe (Payments)] -> [Resend (Email)] -> [Uploadthing (File Storage)] Include an interactive diagram generated by CodeDashboard or draw one using Excalidraw/Miro.
Technology stack
A categorized list of all technologies. Group by layer: frontend, backend, database, infrastructure, and third-party services.
Example
Frontend: React 19, Next.js 15, Tailwind CSS 4, shadcn/ui Backend: Next.js API routes, tRPC Database: Supabase (Postgres), Prisma ORM Infrastructure: Vercel (hosting), GitHub Actions (CI) Services: Stripe (payments), Resend (email), Uploadthing (files)
Directory structure
The top-level directory structure with a one-line explanation of what each folder contains.
Example
src/ app/ # Next.js App Router pages and layouts components/ # React components (ui/ for primitives, feature/ for domain) lib/ # Shared utilities, API clients, and business logic types/ # TypeScript type definitions and Zod schemas server/ # tRPC routers and server-side procedures prisma/ # Database schema and migrations public/ # Static assets
Key modules
The 5-8 most important modules/directories with a paragraph each explaining what they do and how they work.
Example
Authentication (src/lib/auth/): Uses Supabase Auth with email/password and GitHub OAuth. Session management is handled by middleware that refreshes tokens on every request. Protected routes check for a valid session in the server component. Task management (src/server/routers/tasks.ts): The core domain logic. Tasks have a status (todo, in_progress, review, done), an assignee, a due date, and a priority. Status transitions are validated server-side. Position ordering uses a fractional index system for drag-and-drop.
Data flow for key features
Trace 2-3 important user flows through the system, naming the specific files involved.
Example
Creating a task: 1. User fills the form in TaskCreateDialog (src/components/tasks/task-create-dialog.tsx) 2. Form submits via tRPC mutation (src/server/routers/tasks.ts:create) 3. Server validates input with Zod, checks project membership 4. Task inserted into tasks table with Prisma 5. Real-time subscription notifies other clients via Supabase Realtime 6. Task appears in the kanban board (src/components/board/board-column.tsx)
Conventions and patterns
Document the patterns and conventions that are not obvious from reading individual files.
Example
- All API routes use tRPC with Zod input validation. - Components follow the container/presenter pattern: "smart" components in feature/ fetch data, "dumb" components in ui/ render it. - Error handling uses a centralized error boundary (src/components/error-boundary.tsx). - Environment variables are accessed through a typed config file (src/lib/config.ts), never directly via process.env.
Automate this with CodeDashboard
CodeDashboard generates most of this document automatically. The architecture diagram, technology stack, directory structure (repo tour), key modules (frontend/backend summaries), and data flow sections are all part of the standard analysis. Run it on the repo and use the dashboard as your codebase overview, or export the relevant sections into this template.
Get this template as Markdown
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