Blockscout vs Etherscan

Blockscout is the open-source, EVM-compatible block explorer behind dozens of public chain explorers (Ethereum mainnet, its L2s, and more), and its REST v2 API exposes the same block, address, token, and transaction data that powers those explorer UIs. No signup or API key is required for the per-instance hosted public REST API, though anonymous callers are rate-limited per endpoint (confirmed live: `x-ratelimit-limit` varies by route, e.g. 180 on an address lookup vs. 10 on `/stats`); docs.blockscout.com also flags this per-instance API for deprecation in favor of a separate, paid, API-key-gated multichain "PRO API," though the free per-instance API this entry tracks was still live and keyless as of this run's probe. Every response is JSON.

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.