How to Use Etherscan's API: A Comprehensive Guide

Ethereum offers two primary APIs—Web3 and JSON-RPC—alongside additional Geth APIs. However, developers often face limitations, such as cumbersome processes for fetching transaction timestamps (requiring block ID lookups via transaction hashes).

To bridge these gaps, Etherscan provides a suite of public APIs that enhance Ethereum application development.

Etherscan API Overview

Etherscan.io offers a robust API collection designed to simplify blockchain interactions. Below, we break down key modules and their functionalities.

Key Features

• Simple HTTP GET requests with clear examples in the documentation.
• Diverse modules: Accounts, smart contracts, transactions, blocks, event logs, tokens, and utilities.

Account APIs

1. Get Single Account Balance

Retrieve the Ether balance of any address.

Request Example:

https://api.etherscan.io/api?module=account&action=balance&address=0xddbd2b932c763ba5b1b7ae3b362eac3e8d40121a&tag=latest&apikey=YourApiKeyToken

Parameters:

• module=account
• action=balance
• address: Target wallet address.
• tag=latest (default).

Response:

{"status":"1","message":"OK","result":"670456215218885498951364"}

2. Get Multiple Account Balances

Fetch balances for up to 20 addresses in one call.

Request Example:

https://api.etherscan.io/api?module=account&action=balancemulti&address=0xddbd2b932c763ba5b1b7ae3b362eac3e8d40121a,0x63a9975ba31b0b9626b34300f7f627147df1f526&tag=latest&apikey=YourApiKeyToken

Response:

{
  "result": [
    {"account": "0xddbd2b932c763ba5b1b7ae3b362eac3e8d40121a", "balance": "40807168564070000000000"},
    {"account": "0x63a9975ba31b0b9626b34300f7f627147df1f526", "balance": "332567136222827062478"}
  ]
}

3. Get Normal Transactions

Fetch standard blockchain-recorded transactions.

Request Example:

https://api.etherscan.io/api?module=account&action=txlist&address=0xddbd2b932c763ba5b1b7ae3b362eac3e8d40121a&startblock=0&endblock=99999999&sort=asc&apikey=YourApiKeyToken

Parameters:

• action=txlist
• sort=asc (ascending) or desc (descending).

Response: Includes blockHash, timestamp, value, and more.

4. Get Internal Transactions

Retrieve non-blockchain-recorded transactions (e.g., failed transactions).

Request Example:

https://api.etherscan.io/api?module=account&action=txlistinternal&address=0x2c1ba59d6f58433fb1eaee7d20b26ed83bda51a3&apikey=YourApiKeyToken

Note: Use txhash parameter to query specific transaction details.

5. Get ERC-20 Token Transfers

Track token movements for specific contracts.

Request Example:

https://api.etherscan.io/api?module=account&action=tokentx&contractaddress=0x9f8f72aa9304c8b593d555f12ef6589cc3a579a2&address=0x4e83362442b8d1bec281594cea3050c8eb01311c&apikey=YourApiKeyToken

Response: Includes tokenSymbol, tokenDecimal, and transfer value.

Smart Contract APIs

Get Contract ABI

Fetch the Application Binary Interface (ABI) to interact with smart contracts.

Request Example:

https://api.etherscan.io/api?module=contract&action=getabi&address=0xBB9bc244D798123fDe783fCc1C72d3Bb8C189413&apikey=YourApiKeyToken

Use Case: ABIs enable direct method calls to contracts.

Rate Limits

• Without API Key: 5 requests/sec.
• With API Key: Higher limits (specified in your account).

FAQ

1. What’s the difference between normal and internal transactions?

• Normal: Recorded on-chain.
• Internal: Off-chain (e.g., failed transactions).

2. Can I use these APIs on testnets?

Yes! Replace the domain with api-rinkeby.etherscan.io for Rinkeby.

3. How do I handle pagination?

Use page and offset parameters (e.g., offset=10 for 10 records per page).

4. What’s the maximum addresses for balancemulti?

20 addresses per request.

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