CheckedIn is a Solana-powered habit tracker that records your daily focus or study sessions on-chain.
Each check-in becomes a signed Solana transaction, creating a tamper-evident streak that any app can verify and build on.

1. Overview
2. Features
3. Architecture
   • Smart Contract (Solana Program)
   • Web App (Frontend)
4. Solana Tools & Stack
5. Why Solana?
6. Getting Started
   • Prerequisites
   • Clone & Install
   • Environment Variables
7. Running the Project
   • Local Program + Devnet
   • Running the Web App
8. Program Details
   • Accounts
   • Instructions
9. Frontend Details
   • UI Flow
   • Key Components
10. Testing
11. Future Improvements
12. License

CheckedIn demonstrates how simple, everyday actions—like finishing a study session—can be written to Solana as verifiable events.
Users connect a wallet, check in once per day, and the Solana program enforces streak logic on-chain.

• Network: Solana devnet
• Smart Contract: Rust + Anchor
• Frontend: Next.js, TypeScript, Tailwind CSS

• On-chain daily check-ins (one per calendar day)
• Automatic streak increment / reset logic at the program level
• Wallet-based identity: your streak is tied to your Solana address
• Clean, minimal UI (“CheckedIn”) optimized for quick daily use
• Devnet-ready demo for hackathons and presentations

High-level architecture:

• Solana Program (Anchor/Rust)

  • Stores user streak state in a PDA derived from ["user-streak", user_pubkey].
  • Enforces business rules: one check-in per day, increment/reset logic.

• Web App (Next.js / TypeScript)

  • Connects to Phantom and other wallets via Solana Wallet Adapter.
  • Uses Anchor’s TypeScript client to talk to the on-chain program.
  • Displays current streak and last check-in date for the connected wallet.

• Framework: Anchor
• Core account: UserStreak
  • authority: Pubkey – wallet that owns the streak
  • streak: u64 – current streak length
  • last_check_in: i64 – last check-in timestamp (or day index)

• Framework: Next.js (App Router)
• Styling: Tailwind CSS
• Language: TypeScript
• Wallet Integration: @solana/wallet-adapter-react + @solana/wallet-adapter-wallets

• Anchor – declarative accounts, IDL, migrations, and test runner.
• @solana/web3.js – RPC client, transactions, and PDA derivation.
• Solana Wallet Adapter – plug-and-play browser wallet support.
• Solana devnet – public test network used for this demo.

• Low fees & fast finality: Ideal for daily micro-transactions like check-ins.
• Account model: PDAs make it easy to map “one user → one streak account”.
• Mature dev tooling: Anchor and wallet adapter significantly reduce boilerplate.
• Composability: Other Solana programs can later read streak data for reputation, rewards, or gating.

• Node.js (LTS)
• Yarn or pnpm or npm
• Rust + Cargo
• Solana CLI
• Anchor CLI
• A Solana wallet (e.g., Phantom) configured for devnet

Backend: https://github.com/DanielG6205/mbc-checkedin-anchor