# Technology Stack

**Analysis Date:** 2026-03-11

## Languages

**Primary:**
- Go 1.25.0 - Backend REST API, SPA server, database migrations
- TypeScript 5.9.3 - Frontend React application, type-safe client code
- SQL - Database schema and migrations (PostgreSQL)

**Secondary:**
- HTML/CSS - Frontend markup and styling (via React/Tailwind)
- JavaScript - Runtime for frontend (via TypeScript compilation)

## Runtime

**Environment:**
- Go 1.25.0 - Backend runtime (production: Alpine-based Docker)
- Node.js 19+ (implied via Bun) - Frontend build only
- Bun 1.x - JavaScript package manager and runtime

**Package Manager:**
- Bun - JavaScript/TypeScript package manager
  - Lockfile: `frontend/bun.lock` (present)
- Go modules - Go dependency management
  - Lockfile: `backend/go.mod`, `backend/go.sum` (present)

## Frameworks

**Core:**
- React 19.2.0 - Frontend UI framework
- Chi v5.2.5 - Go HTTP router with middleware support
- Vite 7.3.1 - Frontend build tool and dev server

**UI/Styling:**
- Tailwind CSS 4.2.1 - Utility-first CSS framework with Vite plugin
- shadcn/ui 4.0.0 - Component library built on Radix UI
- Radix UI 1.4.3 - Headless UI component primitives

**Charting/Data Visualization:**
- Recharts 2.15.4 - React charting library for budget visualization

**Internationalization:**
- i18next 25.8.14 - Frontend i18n framework
- react-i18next 16.5.6 - React bindings for i18next

**Routing:**
- React Router DOM 7.13.1 - Frontend client-side routing

## Key Dependencies

**Critical:**
- jackc/pgx/v5 v5.8.0 - PostgreSQL driver and connection pooling (pgxpool)
- golang-jwt/jwt/v5 v5.3.1 - JWT token generation and validation for session auth
- golang.org/x/crypto v0.48.0 - bcrypt password hashing

**Infrastructure:**
- chi/v5 v5.2.5 - HTTP router with CORS and compression middleware
- chi/cors v1.2.2 - CORS middleware for Go
- google/uuid v1.6.0 - UUID generation for database IDs
- shopspring/decimal v1.4.0 - Precise decimal arithmetic for currency amounts
- tailwindcss/vite v4.2.1 - Tailwind CSS Vite integration

**Frontend Utilities:**
- clsx 2.1.1 - Conditional className utility
- tailwind-merge 3.5.0 - Merge and deduplicate Tailwind CSS classes
- class-variance-authority 0.7.1 - Type-safe component variant system
- lucide-react 0.577.0 - Icon library for React
- @fontsource-variable/geist 5.2.8 - Geist variable font

**Dev Tools:**
- TypeScript ESLint 8.48.0 - Linting for TypeScript/JavaScript
- ESLint 9.39.1 - Base linting framework
- @vitejs/plugin-react 5.1.1 - Vite plugin for React (JSX/Fast Refresh)

## Configuration

**Environment:**
- Configuration via environment variables:
  - `DATABASE_URL` - PostgreSQL connection string (default: `postgres://simplefin:simplefin@localhost:5432/simplefindb?sslmode=disable`)
  - `SESSION_SECRET` - Secret for JWT signing (default: `change-me-in-production`)
  - `PORT` - Server port (default: `8080`)
  - `OIDC_ISSUER` - OIDC provider issuer URL (optional)
  - `OIDC_CLIENT_ID` - OIDC client identifier (optional)
  - `OIDC_CLIENT_SECRET` - OIDC client secret (optional)
- Env file: Not detected - uses environment variables at runtime

**Build:**
- Frontend: `frontend/vite.config.ts` - Vite configuration with React and Tailwind plugins
- Frontend: `frontend/tsconfig.app.json` - TypeScript compiler options (ES2022, strict mode)
- Frontend: `frontend/tsconfig.node.json` - TypeScript config for build tools
- Frontend: `frontend/eslint.config.js` - ESLint configuration
- Frontend: `frontend/components.json` - shadcn/ui component configuration
- Backend: Multi-stage Docker build via `Dockerfile` (Bun frontend → Go backend → Alpine)

## Platform Requirements

**Development:**
- Docker and Docker Compose (for local PostgreSQL)
- Go 1.25.0+
- Bun or Node.js 19+ (frontend)
- PostgreSQL 16 compatible (for `docker compose up db`)

**Production:**
- Alpine Linux (via Docker image from `Dockerfile`)
- PostgreSQL 16 (external database)
- Single Docker image deployment: embeds frontend build and migrations

## Deployment

**Build Strategy:**
- Multi-stage Docker build (file: `Dockerfile`):
  1. Stage 1 (Bun): Build frontend React app → `frontend/dist`
  2. Stage 2 (Go): Download Go dependencies, embed frontend dist and migrations, compile binary
  3. Stage 3 (Alpine): Minimal runtime image with single `/server` binary
- Binary embeds:
  - Frontend static files via `embed.FS` at `cmd/server/frontend_dist/`
  - SQL migrations via `embed.FS` at `cmd/server/migrations/`

**Compose Configuration:**
- File: `compose.yml`
- Services:
  - `app`: Built from Dockerfile, exposes port 8080
  - `db`: PostgreSQL 16 Alpine, exposes port 5432, volume: `pgdata`
- Health checks: PostgreSQL readiness check before app startup

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*Stack analysis: 2026-03-11*