JavaScript, from JSON.parse(), fetch() with response.json() and axios
The first character JSON.parse saw was <, and no JSON document can start with that. It almost always means the server sent back an HTML page where your code expected JSON, so the real problem is in the request, the URL or the server, and the JSON itself is fine.
This is what JSON.parse was handed, a 404 page. The fix is in the request, so Repair cannot help here.
a <!DOCTYPE html>
<html lang="en">
<head>
<title>404 Not Found</title>
</head>
<body>
<h1>Not Found</h1>
<p>The requested URL /api/order was not found on this server.</p>
</body>
</html>
A typo in the path, a missing /api prefix or a relative URL that resolves somewhere else all return the server's HTML 404 page. Open the request in your browser's Network tab and look at the Response, if it starts with <!DOCTYPE html> you're hitting the wrong address.
Frameworks like Express, Django, Rails and Laravel render an HTML error page on a 500, and reverse proxies like nginx do the same for a 502 or 504. Check the status code before you parse, so a failed request throws a clear error instead of a confusing parse error.
const response = await fetch('/api/orders')
if (!response.ok) {
throw new Error(`Request failed with status ${response.status}`)
}
const type = response.headers.get('content-type') ?? ''
if (!type.includes('application/json')) {
const body = await response.text()
throw new Error(`Expected JSON but got ${type}: ${body.slice(0, 120)}`)
}
const data = await response.json()Single page app dev servers (Vite, Create React App, webpack) answer any unknown path with index.html. If your API runs on another port and the proxy isn't set up, /api/orders comes back as your app's HTML. Point the request at the API's real origin or configure the dev server proxy.
When a session expires, many apps redirect to a sign-in page. fetch follows the redirect and hands you the login page's HTML. Check response.redirected or response.url, and handle 401 and 403 before parsing.
Position 0 is the very first character of the text. The parser failed before reading anything valid, which is why this error nearly always points at a response that was never JSON in the first place.
Open your browser's developer tools, go to the Network tab, click the request and look at the Response panel. In code, call response.text() instead of response.json() and log the first few hundred characters.
Postman sends the request exactly as you typed it. Your app may be adding a base URL, missing an auth header or cookie, or going through a dev server proxy, any of which can turn the same request into an HTML page.