If you're using OAuth 2.0 to secure your API — that's great. But if you're NOT using PKCE with it, your API might still be vulnerable. Most developers implement OAuth 2.0 and think they're done. The truth? OAuth alone is open to interception attacks . What's the problem? When a user logs in via OAuth 2.0, an authorization code is returned in the URL. A malicious app on the same device can intercept that code. And exchange it for an access token. Without ever knowing the user's password. How PKCE fixes this PKCE (Proof Key for Code Exchange) adds two things: A code_verifier — a random secret string A code_challenge — SHA-256 hash of that verifier The verifier is sent with the token request. The server checks it matches the original challenge. If someone intercepts the code — they can't use it. Because they don't have the verifier.…