# Firebase callable functions: error INTERNAL (functions/internal)
> A Firebase callable function returns INTERNAL with no details. The function threw a plain error. Throw HttpsError, read the logs, and check the region.
Canonical: https://app369.com/fix/firebase-functions-callable-internal-error/
Last updated: 2026-11-09
INTERNAL is the error a Firebase callable function returns to the client when the function throws anything other than an HttpsError. The client sees only INTERNAL, so the real error is in the function logs.
**Short answer**
Open the function’s logs in the Firebase console or Google Cloud to find the real error. Catch errors in the handler and throw an HttpsError with a code and a message the client can show. If the logs show no call at all, check the client uses the region and name you deployed.
Rather not fix it yourself? [**App Fix Ticket**](https://app369.com/fixed-price/flutter-firebase-bug-fix/) starts with a fixed-price diagnosis, then a fixed price for the fix before any fix work.
## **Why the client gets INTERNAL, and the fix**
1. 01 ### **A plain error escapes the handler**
> “If an error other than an HTTPS error is thrown from your functions, your client instead receives an error with the message INTERNAL and the code internal.” [**Firebase, Call functions from your app**](https://firebase.google.com/docs/functions/callable) A failed database write, a missing environment value or a bug throws a normal Error, and the client only sees INTERNAL. Log the real error and throw an HttpsError.```
const { onCall, HttpsError } = require('firebase-functions/https');
const { logger } = require('firebase-functions');
exports.createOrder = onCall(async (request) => {
if (!request.auth) {
throw new HttpsError('unauthenticated', 'Sign in first.');
}
try {
return await saveOrder(request.data);
} catch (err) {
if (err instanceof HttpsError) throw err;
logger.error(err);
throw new HttpsError('internal', 'Could not save the order.');
}
});
```
2. 02 ### **The client calls a different region**
> “To call a function running in any location other than us-central1, you must set the appropriate value at initialization.” [**Firebase, Call functions from your app**](https://firebase.google.com/docs/functions/callable) A function deployed to europe-west1 and a client left on the default region never meet; the client may see INTERNAL or NOT_FOUND. Pass the region when you get the functions instance, such as getFunctions(app, 'europe-west1').
3. 03 ### **The function is onRequest, not onCall** httpsCallable expects a function written with onCall. An onRequest function returns a plain HTTP response, so call it with fetch or rewrite it as onCall.
4. 04 ### **The function crashed or timed out** Out-of-memory and timeout failures are recorded in the logs, while the client may see INTERNAL, UNAVAILABLE or DEADLINE_EXCEEDED. Raise the memory or timeout, or move long work to a background trigger.
Checked against the vendor’s docs on November 9, 2026: [Firebase docs: Call functions from your app](https://firebase.google.com/docs/functions/callable); [Firebase docs: Cloud Functions locations](https://firebase.google.com/docs/functions/locations).
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Related: [**Firebase Functions 403 Forbidden**](https://app369.com/fix/firebase-functions-403-forbidden/) · [**Firebase Functions timeout**](https://app369.com/fix/firebase-functions-timeout/) · [**Firebase Functions CORS error**](https://app369.com/fix/firebase-functions-cors-error/) · [**Firebase Functions secret undefined**](https://app369.com/fix/firebase-functions-secret-undefined/)
Questions
## **More on this error**
**Why does the client only see INTERNAL? **+
Firebase passes the code, message and details to the client only for an HttpsError. Other errors stay in the logs and reach the client as INTERNAL.
**Should I send the raw error to the client? **+
No. Log the full error on the server and send the client a short message it can show. Stack traces can expose details of your backend.
**Can you fix it for me? **+
If one bug is the whole problem, the App Fix Ticket covers it: a written diagnosis first, then the fix. If the app has more going on, the Launch Check is a written check of the whole app. Each issue found is rated critical, high, medium or low, with where it is and how it was confirmed. No issues worth fixing, no charge. If the Launch Check finds nothing rated medium or higher, Simon refunds the full $450. You keep the report either way. This applies to the first 10 Launch Checks bought after October 30, 2026.
A different error?
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