---
title: numbers.e164_taken
description: The E.164 number is already in inventory.
summary: >-
  Returned by POST /v1/numbers/byo when the number is already registered on
  Sautikit — either as a platform number or as another workspace's BYO number.
  Numbers are globally unique across the platform.
date: 2026-08-06T00:00:00.000Z
type: error
---


## Summary

`numbers.e164_taken` means the E.164 number you tried to add already exists in Sautikit's inventory.

## Cause

The box routes an inbound call by the dialed number alone, so a duplicate E.164 across two workspaces would be ambiguous about which one should receive it. Number uniqueness is therefore enforced globally, not just within your workspace — the number may already be:

- one of your own numbers, added or claimed previously,
- a platform (Sautikit-provisioned) number belonging to another workspace, or
- a BYO number another workspace already registered.

## Resolution

Double-check the E.164 you are submitting — a typo (missing `+`, wrong country code, extra digit) is the most common cause. If the number is genuinely already active on this workspace, it does not need to be added again:

```bash
curl "https://api.sautikit.com/v1/numbers" \
  -H "Authorization: Bearer $SAUTIKIT_API_KEY"
```

If you believe another party has registered a number you legitimately own, contact support.

## Example response

```json
{
  "error": {
    "code": "numbers.e164_taken",
    "message": "that number is already registered on Sautikit",
    "request_id": "req_01900000abc"
  }
}
```

## Next steps

- [Numbers concepts — bring your own SIP trunk](/developers/concepts/numbers#bring-your-own-sip-trunk)
- [Numbers API](/developers/api#numbers) — list numbers already on this workspace