Build Your Own Mini Blockchain with Shannon SDK from Pocket Network

🌟 Introduction

Ever wanted to create your own lightweight blockchain in minutes? Thanks to Pocket Network's open-source Shannon SDK, it's now possible to build a fully working blockchain for education, prototyping, or specialized apps – all in JavaScript/TypeScript.

In this guide, we’ll show you how to:

• Initialize a new blockchain locally
• Customize its logic using JS
• Broadcast transactions and view block behavior

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🧰 Prerequisites

Before starting, make sure you have:

• Node.js (v18+)
• Git installed
• Basic familiarity with JavaScript or TypeScript

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⚙️ Step 1: Install the Shannon CLI

Install the global CLI tool:

bash
npm install -g @pokt-foundation/shannon-cli
Check installation:

bash
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shannon --version
🚀 Step 2: Initialize Your Blockchain
bash
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shannon init my-chain
cd my-chain
This creates a scaffold project with the following structure:

arduino
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my-chain/
├── app/         ← Your custom logic
├── config/      ← Chain configuration
├── scripts/     ← Dev tools
└── .shannonrc   ← CLI settings
▶️ Step 3: Start the Dev Node
bash
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shannon dev
This launches a local node that watches your code and reloads on save. You'll see logs of block processing and transaction handling.

🔁 Hot reloading included out-of-the-box!

✍️ Step 4: Write Custom Logic
Let’s update app/index.ts to handle custom transactions:

ts
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export const app = {
  async deliverTx(tx: Uint8Array) {
    const decoded = new TextDecoder().decode(tx);
    console.log("🧾 Received tx:", decoded);
    return { code: 0 };
  }
}
Every time a transaction is received, it will decode and log it.

📡 Step 5: Broadcast a Transaction
Send a transaction using curl or Postman:

bash
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curl -X POST http://localhost:26658 \
-d '{"jsonrpc":"2.0","method":"broadcast_tx_sync","params":["0x48656c6c6f205368616e6e6f6e21"],"id":1}' \
-H "Content-Type: application/json"
In your terminal, you'll see:

yaml
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🧾 Received tx: Hello Shannon!
🧠 How It Works – Visual Guide
Here’s a simple architecture diagram:


Your app logic acts as a handler for each stage:

checkTx(): validate before block inclusion

deliverTx(): execute on block commit

initChain(), endBlock(), etc.: manage state transitions

✅ Why Shannon?
Shannon SDK is great for:

Learning how blockchains handle transactions

Rapid prototyping for Web3 apps

Creating blockchain-based games, voting apps, etc.

Instead of deploying a heavy Ethereum or Cosmos chain, you can simulate behavior in a fast and lightweight setup.

📚 Resources
🔗 Shannon SDK GitHub


📖 Official Docs

🧠 Pocket Network

🛠️ Tendermint Core

💬 Share Your Ideas!
Have you tried Shannon? Got a cool use case or ran into issues? Leave a comment below – let's explore lightweight blockchain apps together!