Multi-blockchain data aggregator platform.
Covalent API is a free Blockchain API that requires apiKey authentication, is served over HTTPS and has unconfirmed CORS support.
Covalent is the leading modular data infrastructure layer that’s dedicated to solving the Long-Term Data Availability and the verifiability problem in AI.
Details from covalenthq.com.

Unified API suite · now live
Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
RPC endpoints for 150+ blockchain networks, including Ethereum, Solana, Polkadot and Hyperliquid
The Covalent API is provided by Covalent Network (covalenthq.com). Covalent is the leading modular data infrastructure layer that’s dedicated to solving the Long-Term Data Availability and the verifiability problem in AI.
Yes. The Covalent API is listed in the Blockchain category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
Yes. The Covalent API uses apiKey authentication, so you need to register for credentials before making requests.
CORS support for the Covalent API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
Yes. The Covalent API is served over HTTPS, so it's safe to use in production.