Cookies in PHP (Remember Me Feature)

Cookies are small pieces of data stored in the browser.

Cookies vs Sessions (clear difference)

• Session: stored on server, browser has only the session id
• Cookie: stored on browser, sent with every request to your domain

Setting a cookie

setcookie("theme", "dark", time() + 60 * 60 * 24 * 30, "/");

That stores theme=dark for 30 days.

Reading a cookie

if (isset($_COOKIE["theme"])) {
  echo "Theme: " . $_COOKIE["theme"];
}

Deleting a cookie

setcookie("theme", "", time() - 3600, "/");

Security note (very important)

Never store sensitive info directly in cookies (like password).
If you do “remember me”, store a random token and validate it on server.

Next: Error handling and debugging in PHP without guessing.