A live test on October 6 found that API3's AirnodeHub can return CoinGecko price data in its familiar JSON format while carrying a verifiable signature in HTTP headers. The check used the provider-compatible interface rather than the MCP workflow or a response wrapped inside a separate data object. This is a review of the current early-access product, not a newly announced release.
The request selected Ethereum and USD through the CoinGecko Airnode's simple-price route. It returned HTTP 200 with a 28-byte JSON body. Separate headers carried the signing address, request hash, signing timestamp and signature. The quoted price was a single observation during the test, not an executable trade price or an assessment of the market.
The test then checked the response locally using the signing address and EIP-191 scheme published in the Airnode's machine-readable document. Recomputing the hash from the requested method, path and query matched the returned request hash. Signature verification passed for the exact received body. Changing the price value in the saved body caused verification to fail.
This matters for software that already reads a provider's response shape. AirnodeHub's HTTP documentation describes a passthrough interface that preserves the upstream response body and sends the attestation separately. Applications can keep their existing data parser, although checking those extra headers still requires verification logic. Only declared routes are exposed; this is not unrestricted access to the provider's entire API.
The current listing also includes trending-search and ranked-market-data operations and labels the available operations free. Those other routes were not tested here. Early-access availability does not establish permanent pricing or a production service guarantee.
The signature belongs to the API3-operated Airnode, not CoinGecko. It binds the response to that signer, the request and a signing time, rather than independently establishing price accuracy or the upstream observation's freshness. The earlier MCP verification walkthrough explains the same distinction through a different interface.