16-CDP-SQL-API-Demo

CDP SQL API Demo — Query Onchain Data with SQL

This tutorial shows how to query onchain data from the Base network using the Coinbase Developer Platform (CDP) SQL API from a simple Node.js app. You will:

• Configure your CDP API key
• Run a query to fetch the latest block on Base
• Run a whale-watching query to find the largest recent USDC transfers

Prerequisites

• Node.js v16+
• A CDP API key with access to the SQL API

Setup

1. Install dependencies:

npm install

2. Create a .env file and set your key:

echo "CDP_CLIENT_API_KEY=YOUR_API_KEY_HERE" > .env

If this repo includes a .env.example, you can also copy it and fill in values:

cp .env.example .env

3. Run the demo:

# Runs both demos: latest block + whale watching (10k sample)
npm start

# Latest block only
npm run latest-block

# Whale watching (top 5 USDC transfers from recent sample)
npm run whales

# Optional: smaller or larger sample window
npm run whales:1k
npm run whales:10k

How it works

The app sends SQL queries to the CDP SQL API endpoint:

• index.js loads the CDP_CLIENT_API_KEY from .env
• runLatestBlockDemo() queries the latest block from base.blocks
• runWhaleWatchingDemo() selects recent Transfer events for USDC on Base from base.events, sorts by value, and prints the top 5

Key files:

• index.js: Main CLI entry with two demos
• package.json: Helpful scripts for running demos

Customization

• Change the token by editing DEFAULT_USDC_BASE_ADDRESS in index.js
• Adjust the sample size with npm run whales -- <limit> or use whales:1k/whales:10k

Notes

• USDC has 6 decimals. The demo prints both an exact usdc_exact string and a human-friendly usdc_formatted approximation.
• Results are derived from a recent sample (LIMIT clause). Increase the limit to widen the sample.

Troubleshooting

• "Please set CDP_CLIENT_API_KEY": Ensure .env has CDP_CLIENT_API_KEY and you restarted the process after changes.
• 401/403 errors: Check that your API key is valid and has required permissions.