API Trading Fundamentals

An exchange's API exposes programmatically the same actions available on its website -- reading market data, checking balances, and placing or cancelling orders -- authenticated using an API key and secret rather than a login session. Most exchanges also offer public, unauthenticated endpoints for market data (this site's own prices and charts use exactly this kind of endpoint) that require no account at all.

Authenticated endpoints, by contrast, sign every request cryptographically so the exchange can verify it genuinely came from the key's owner and hasn't been tampered with in transit.