---
title: "Read SIP registration credentials for a number"
method: GET
path: "/v1/numbers/{e164}/sip"
---

# Read SIP registration credentials for a number

`GET /v1/numbers/{e164}/sip`

## Request

- Base URL: `https://volai.cz`
- URL: `https://volai.cz/v1/numbers/{e164}/sip`
- Auth: HTTP bearer

The number's SIP details - for your own softphone/PBX and for a voice platform's outbound trunk (ElevenLabs, Vapi...). Step-by-step setup is on the [SIP](https://volai.cz/en/docs/sip).

## Path parameters

- `e164` string, required

## Response `200`

SIP credentials

- object
  - `server` string, required: Registration domain for a softphone or PBX (SIP REGISTER). Not for platform outbound trunks - see outboundTrunkAddress.
  - `username` string, required: SIP username for this number, equal to the line id.
  - `password` string, required: SIP password for this number.
  - `outboundTrunkAddress` string, required: Address for your platform's outbound SIP trunk (ElevenLabs outbound_trunk_config.address). Use exactly this value regardless of whether it matches server - a different address means the call is not routed on the network and the platform reports a timeout, with nothing left in the call history.
  - `port` integer, required: SIP signalling port (tcp and udp).
  - `transport` 'tcp' | 'udp', required: Recommended SIP transport for the outbound trunk and softphone registration. tcp is recommended: a large INVITE with SDP can exceed the UDP MTU and the platform then refuses to send it at all; udp works too.
  - `inboundSignallingCidrs` string[], required: Where our INVITEs to your PBX or platform come from - allowlist for your inbound trunk.

## Other responses

- `400`: Error codes: validation (request).
- `401`: Error codes: unauthorized (request).
- `403`: Error codes: account_suspended (account).
- `404`: Error codes: not_found (account).
- `429`: Error codes: rate_limited (busy).
- `500`: Error codes: internal_error (service).
- `502`: Error codes: sip_credentials_unavailable (service).

---

[API](https://skmtc.dev/volai/apis/volai-rest-api.md) · [All operations](https://skmtc.dev/volai/apis/volai-rest-api/llms.txt) · [OpenAPI document](https://skmtc.dev/volai/apis/volai-rest-api/revisions/12029b05e2fa?raw)