Blockchain — entry 005 of 11
Etherscan
Etherscan's API exposes the same account balances, transactions, contract source, and gas-tracker data shown on the block explorer, addressed to Ethereum mainnet and its testnets through a single query-parameter-based endpoint. Calls against the older V1 endpoint now return a deprecation notice pointing at the documented V2 migration, so new integrations should build against V2 directly. Free-tier keys cover light use, with paid plans unlocking higher rate limits.
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<a href="https://greatapis.com/api/etherscan/"><img src="https://greatapis.com/badge/etherscan.svg" alt="Scored 75 on greatapis.com"></a>Auth quickstart
- Get a key at the provider
- Send it on every request as a header
Authorization: <key> - The exact header isn't documented — Authorization is a common default; confirm in the provider's docs.
Your key is stored only in this browser (localStorage) and sent directly to the API — never to greatapis.
Developer reference
Free: 3 calls/second, up to 100,000 calls/day; Standard: 10 calls/second, up to 200,000 calls/day; Advanced: 20 calls/second, up to 500,000 calls/day; Professional: 30 calls/second, up to 1,000,000 calls/day