Brew Log

A coffee brewing journal for dialing in your pour-over, espresso, and everything in between — log your beans and brews, get AI coaching on your last cup, and share your best recipes with the community.

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Overview

Brew Log is a full-stack web app for coffee enthusiasts who want to brew more deliberately. Record each bag of beans and every brew — grind, dose, water, temperature, time, TDS, extraction yield, and a full taste profile — then let an AI brew master read your notes and tell you what to change next time. Make a brew public to share it on the community feed, where other members can rate it.

It doubles as a reference implementation of a modern Next.js App Router stack: server components and server actions end to end, Better Auth for authentication, Drizzle + Neon for the database, the Vercel AI SDK for AI features, and an editorial design system built on Tailwind and Base UI.

Features

• Beans & brews — Full CRUD for your coffee library and brew log, with detailed metrics (dose, water ratio, temperature, time, TDS, extraction yield) and a five-axis taste profile.
• AI bean scan — Photograph a bag and Gemini auto-fills the roaster, origin, process, roast level, and tasting notes.
• AI brew master — Ask an AI coach to analyze any brew and suggest concrete adjustments for your next cup; advice is cached per brew so re-viewing never re-bills the model.
• Community & sharing — Publish brews to the Explore feed, browse public profiles at /u/[username], and give other members' brews a 1–5 star rating.
• Authentication — Email/password and Google sign-in via Better Auth, with email verification, forgot/reset password, and change-password flows.
• Internationalization — Ships with English and Traditional Chinese (zh-Hant), switchable per user in Settings.
• Guardrails — Per-user record caps and monthly AI usage counters keep token spend in check, with paginated lists throughout. AI features require a verified email, and sign-ups are rate-limited per IP via Better Auth backed by Upstash Redis — so limits hold across serverless instances and cold starts instead of resetting per invocation.

Tech Stack

Area	Technology
Framework	Next.js 16 (App Router), React 19, TypeScript
Database	Neon Postgres + Drizzle ORM
Auth	Better Auth (email/password, Google, username plugin)
AI	Vercel AI SDK + Google Gemini
Email	Resend
Rate limit	Upstash Redis (Better Auth secondary storage)
Styling	Tailwind CSS v4, Base UI
Deployment	Vercel

Getting Started

Prerequisites

• Node.js 20+ and pnpm
• A Neon Postgres database (or any Postgres connection string)
• API keys for the services you want to enable (Google AI, Google OAuth, Resend)

Setup

1. Install dependencies:

   pnpm install

2. Create a .env file in the project root:

   # Database
   DATABASE_URL="postgresql://..."
   
   # Better Auth
   BETTER_AUTH_SECRET="a-long-random-string"
   BETTER_AUTH_URL="http://localhost:3000"
   
   # Google OAuth (optional — enables "Sign in with Google")
   GOOGLE_CLIENT_ID="..."
   GOOGLE_CLIENT_SECRET="..."
   
   # Google Gemini (optional — enables AI bean scan & brew master)
   GOOGLE_GENERATIVE_AI_API_KEY="..."
   
   # Resend (optional — enables verification & password-reset emails)
   RESEND_API_KEY="..."
   EMAIL_FROM="onboarding@resend.dev"
   
   # Upstash Redis (optional — backs auth rate limiting across instances)
   UPSTASH_REDIS_REST_URL="..."
   UPSTASH_REDIS_REST_TOKEN="..."

3. Push the schema to your database:

   pnpm db:push

4. (Optional) Seed some sample data:

   pnpm db:seed

5. Start the development server:

   pnpm dev

Open http://localhost:3000 to see the app.

Note

AI, Google login, and email features are optional. The app runs without their keys — those specific flows are simply unavailable until you provide them.

Warning

With the default onboarding@resend.dev sender, Resend can only deliver to your own account email. To email real users, verify a domain in Resend and set EMAIL_FROM accordingly.

Scripts

pnpm dev            # Start the development server
pnpm build          # Build for production
pnpm start          # Start the production server (requires build first)
pnpm lint           # Run ESLint

pnpm db:push        # Sync schema changes directly to the DB (development)
pnpm db:generate    # Generate SQL migration files from schema changes
pnpm db:migrate     # Apply generated migrations
pnpm db:studio      # Open Drizzle Studio to browse data
pnpm db:seed        # Seed sample data

Project Structure

src/
├── app/
│   ├── (app)/          # Authenticated app — beans, brews, explore, journal, settings
│   ├── (auth)/         # Login, signup, forgot/reset password
│   └── api/auth/       # Better Auth route handler
├── components/         # Shared UI (editorial design system)
└── lib/
    ├── auth.ts         # Better Auth configuration
    ├── db/             # Drizzle schema, client, and seeds
    ├── i18n/           # Locale config and message catalogs (en, zh-Hant)
    ├── redis.ts        # Upstash Redis client (auth rate-limit storage)
    └── ...             # Ratings, limits, email, formatting helpers

Deployment

The app is built to deploy on Vercel. Set the environment variables above in your project settings, point DATABASE_URL at your production Neon database, and set BETTER_AUTH_URL to your production URL. For Google login, add the production redirect URI in the Google Cloud console.