← Writing

📦 On-Chain Key-Value Storage

2025-04-09 · rust · solana · anchor · project

A Solana smart contract project that demonstrates how to send, store, and update data on-chain using keys. Built with Rust and the Anchor framework.

📚 GitHub Repository

This project explores how to interact with a Solana program by writing and updating user-defined data directly on-chain. It simulates a simple “favorites” manager — where users can send strings or numbers to the chain, associate them with a unique key, and later update those entries.

A great starting point for:

• Understanding persistent on-chain state
• Managing user-specific data using derived accounts
• Creating decentralized CRUD-style apps

🧰 Stack & Tools

• 🦀 Rust (Solana smart contract logic)
• ⚓ Anchor (framework for Solana programs)
• 🧪 Local test validator
• 🧪 Rust unit/integration tests

✨ Features

1. Send Arbitrary Data to the Blockchain

   • Insert a value associated with a custom key.

2. Update Stored Data by Key

   • Modify entries via a transaction that targets a specific key.

3. Simple Chain Storage Pattern

   • Uses Solana accounts to persist user-defined values.

4. Full Test Coverage

   • Rust-based tests validate program logic locally.

🚀 Getting Started

1. 🧪 Start Local Solana Validator

Spin up a local blockchain testnet:

solana-test-validator

2. 🛠 Build and Deploy

Compile and deploy the Anchor program:

anchor build && anchor deploy

3. 👛 Add Wallet

Set your Solana CLI wallet path:

export ANCHOR_WALLET=~/.config/solana/id.json

4. ✅ Run Tests

Ensure everything works as expected with:

cargo test

5. 🔍 View Transactions

Access the local explorer to track activity: http://localhost:8899

🧠 Use Cases & Ideas

• ⭐ Store favorite quotes, URLs, or topics by key
• 🧾 Use it as a base for decentralized note-taking or bookmarking
• 🔑 Extend it with access control and per-user namespaces

📄 License

This project is licensed under the MIT License — free for personal and commercial use.