# croct.identify throws Invalid user ID when passing our numeric customer ID

Asked by tallulah_r on 2024-08-21. Tags: errors, identity, javascript.

Working on an ecommerce site in Tokyo, @croct/plug 0.16 on the storefront.

On login we call `croct.identify(user.id)` where `id` comes from our backend as a
number. The SDK throws "Invalid user ID" every time. The ID itself is valid, it
is the same value our whole platform keys on.

Secondary question while I am here: I set a custom attribute with
`croct.user.edit().set('custom.tier', 'gold').save()` but an audience with
`user's custom.tier is "gold"` never matches, is that related?

## 1 answer

### Accepted answer from Aiko Tanaka (2024-08-21)

Two separate quirks, both easy fixes.

`croct.identify` accepts strings only, so a numeric ID is rejected regardless
of the value. Convert it at the call site:

```js
croct.identify(String(user.id));
```

While you are in that code, note that the `userId` and `token` plug options
are mutually exclusive, in case you ever move identification to init time.

The custom attribute issue is not related, it is its own documented quirk:
custom attributes are written with the `custom.` prefix but queried without
it in CQL. Your write call is correct, the query should be:

```cql
user's tier is "gold"
```

Drop the `custom.` from the audience condition and it will match.

#### Reply from tallulah_r (2024-08-21)

Confirmed, both fixed. The prefix asymmetry is surprising but at least it
is consistent. Thank you.