Show HN: SaveContract – CLI tool to download verified smart contract source code

3 months ago 1

A CLI tool to download verified smart contract source code from Etherscan and other Etherscan-powered block explorers using the official V2 API.

Multi-Chain Support: Download contracts from Ethereum, Base, Arbitrum, Polygon, and any other chain supported by the Etherscan V2 API.
Correct File Structure: Automatically parses the Standard JSON Input format to recreate the correct directory structure and file paths.
Easy to Use: Simple and intuitive command-line interface.
Environment Variable Support: Configure your API key once in a .env file.

You can run savecontract directly using npx without installation.

npx savecontract --address <contract_address> [options]

Or, you can install it globally for easier access:

npm install -g savecontract

savecontract --address <contract_address> --chainid <chain> --apikey <your_api_key> --output <directory>

Long Flag Short Flag Description Default

--address	-a	(Required) The contract address to download.	-
--chainid	-c, -cid	Chain ID or name (e.g., "1", "ethereum", "8453", "base").	"1" (Ethereum)
--output	-o	The output directory for the contract files.	./smartcontracts
--apikey	-k	Your Etherscan API key. Overrides the environment variable.	-
--module	-m	API module to use.	"contract"
--action		API action to use.	"getsourcecode"
--help	-h	Show help.	-
--version	-v	Show version number.	-

An Etherscan API key (from the free tier) is required. You can provide it in two ways:

Via Command Line (highest priority):

savecontract -a 0x... -k YOUR_API_KEY
Via .env file (recommended): Create a .env file in the directory where you are running the command and add your key:

ETHERSCAN_API_KEY=YOUR_API_KEY

1. Download a contract from Base mainnet:

npx savecontract -a 0x03059433BCdB6144624cC2443159D9445C32b7a8 -c base -o ./base_contracts

(This assumes your API key is in a .env file)

2. Download a contract from Ethereum mainnet (default chain):

npx savecontract -a 0xBB9bc244D798123fDe783fCc1C72d3Bb8C189413

3. Specify API key directly for a contract on Polygon:

npx savecontract --address 0x... --chainid polygon --apikey YOUR_API_KEY

This tool supports any chain available on the Etherscan V2 API. Use either the chain ID or one of the convenient names below: