> ## Documentation Index > Fetch the complete documentation index at: https://docs.etherscan.io/llms.txt > Use this file to discover all available pages before exploring further. # Welcome to the Etherscan API > The complete onchain data API for the crypto ecosystem Etherscan is the most used block explorer in crypto, and the [Etherscan API](https://etherscan.io/api) gives you the same reliable data behind it across 60+ EVM chains. It is the reference layer teams trust to verify balances, transfers, internal transactions, and contract activity, with accuracy that holds up in front of users, finance, and compliance. * [**Onchain data API**](/endpoint-overview): balances, transactions, token transfers, contract source code, logs, gas, and stats through REST endpoints. * [**Etherscan Metadata**](/metadata/introduction): the identity layer of names, labels, and reputation for addresses, the same as on etherscan.io. Use it alone or alongside the onchain data API. ## Get Started Create your Etherscan API key and make your first API call. Connect agents to live data with MCP, the CLI, and skills. All 60+ EVM chains under one key. Set `chainid` to choose one. The calls per second and daily limits for each plan. See which endpoints power each page on etherscan.io. ## Use Cases Token balances, transactions, and NFT holdings across every chain. Build with `tokenbalance`, `txlist`, `tokennfttx`. Records for filings and audits: internal transactions, transfers, historical balances, and name tags. Screeners, monitoring, and risk dashboards. Build with `getaddresstag`, `getsourcecode`, `fundedby`. Dashboards from transfers, holders, network stats. Build with `dailytx`, `tokenholderlist`, `getlogs`.