---
title: Use a Sautikit Number as a SIP Trunk for Your PBX
description: >-
  Give an office PBX a Kenyan number as a register-based SIP trunk. The settings
  any PBX needs, how calls and caller ID work, and what it costs.
summary: >-
  Any PBX that supports register-based SIP trunks can use a Sautikit number as
  its line: server sip.sautikit.com, port 5080, UDP, and a generated username
  and password.
date: 2026-09-23T00:00:00.000Z
type: guide
---


## Summary

A Sautikit number works as a SIP trunk for any PBX that supports register-based SIP trunks, the kind where the PBX signs in to the provider with a username and password. Claim a number (KES 116/month including VAT, no setup fee), add a device under its **SIP & Devices** tab, and enter the details in your PBX's trunk settings: server `sip.sautikit.com`, port **5080**, transport UDP, and the generated username and password. Incoming calls to the number are free; outgoing calls cost KES 3.00 a minute, billed per second.

## What you need

- **A Sautikit number.** KES 116 a month including VAT, no setup fee, live in seconds from the console or the API. Pay from a prepaid KES wallet topped up with M-Pesa or card.
- **A PBX that supports register-based SIP trunks.** Most PBX software calls this a "register trunk", "registration-based trunk" or "SIP trunk with registration". If your PBX can only accept trunks by IP address with no username and password, this guide does not apply.
- **Administrator access** to the PBX and internet access from it.

## How it works

The PBX signs in to Sautikit the same way a desk phone does: one username, one password, one registration. Sautikit then sends calls for your number to the PBX, and the PBX sends outgoing calls to Sautikit. Your PBX keeps doing everything it already does: extensions, ring groups, menus, call transfer between staff.

A few things follow from that:

- **The PBX counts as one device** on the number. Do not reuse its username in a desk phone or softphone; add a separate device for anything else.
- **Caller ID is your Sautikit number.** Sautikit presents the number the credential belongs to on outgoing calls, whatever caller ID the PBX sets, so nobody can send calls from a number you do not own.
- **Calls between your PBX extensions never reach Sautikit**, so they cost nothing on Sautikit.
- **Each number is one line identity.** If you want several numbers on the PBX, claim each one and add a trunk for each.

## Get your SIP details from Sautikit

In the [Sautikit console](https://app.sautikit.com), open **Numbers**, pick the number, go to the **SIP & Devices** tab and click **+ Add device**. Label it with the PBX's name. Copy the username and password straight away; if you lose them, click **SIP setup** on the device's row to see them again.

From the API, one call creates the credential. The response carries `username`, `password`, `host`, `port`, `transport` and `realm`:

```bash
curl -s -X POST "https://api.sautikit.com/v1/numbers/$NUMBER_ID/sip-credentials" \
  -H "Authorization: Bearer $SAUTIKIT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"label": "Office PBX"}'
```

The same call in JavaScript, printing what to type into the PBX:

```js
const res = await fetch(
  `https://api.sautikit.com/v1/numbers/${process.env.NUMBER_ID}/sip-credentials`,
  {
    method: "POST",
    headers: {
      Authorization: `Bearer ${process.env.SAUTIKIT_API_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({ label: "Office PBX" }),
  },
);

const cred = await res.json();
console.log(`Server:    ${cred.host}`);
console.log(`Port:      ${cred.port}`);
console.log(`Transport: ${cred.transport}`);
console.log(`Username:  ${cred.username}`);
console.log(`Password:  ${cred.password}`);
```

The full request and response are in the [API reference](/developers/api/createSipCredential).

## PBX trunk settings

Field names differ between PBX products. These are the values, with the names you are most likely to see:

| PBX field | Value |
|---|---|
| Trunk type | register trunk (registration with username and password) |
| Server, host, registrar, proxy or SIP server | `sip.sautikit.com` |
| Port | `5080` |
| Domain or realm | `sip.sautikit.com` |
| Transport | UDP |
| Username, user ID or account | your generated username |
| Authentication name or auth ID | your generated username (the same value) |
| Password or secret | your generated password |
| Outbound proxy | leave empty |
| Register | yes |

**Port 5080 is the setting most often wrong.** 5060 is the usual SIP default, and many PBXs fill it in for a new trunk. Sautikit listens on 5080, and a trunk left on 5060 never registers. If your PBX has no separate port field, write the server as `sip.sautikit.com:5080`.

## Steps

1. Create the trunk in your PBX as a register-based SIP trunk and enter the values above.
2. Save and check the trunk's status. Most PBXs show "registered" or a check mark within a minute.
3. Add an **inbound route** that sends calls arriving on this trunk to an extension, ring group or menu. The trunk carries one number, so the route does not need to filter by the dialled number.
4. Add an **outbound route** that sends the calls you choose (for example numbers starting with `0` or `+254`) out through this trunk, and allow the right extensions to use it.
5. Make a test call both ways (below).

For worked examples with exact screens, see:

- [Connect a Yeastar P-Series PBX](/developers/guides/connect-yeastar), a register trunk step by step.
- [Connect a Grandstream phone](/developers/guides/connect-grandstream-phone), [MicroSIP](/developers/guides/microsip-kenya-number) and [Zoiper](/developers/guides/zoiper-kenya-number), if you would rather register phones directly with no PBX.

## Make a test call

From an extension, dial your own mobile number through the outbound route. Your mobile should show your Sautikit number. Then call the Sautikit number from your mobile and confirm it reaches the destination in your inbound route.

## Troubleshooting

**The trunk never registers.** Check the port is 5080 and the transport is UDP. Check the server and domain are `sip.sautikit.com` with no `sip:` prefix. Check the PBX can reach the internet and that a firewall is not blocking outgoing UDP.

**Registration is refused.** The password is wrong or has a stray space. Copy it again with **SIP setup** on the device's row. The username and the authentication name must both be the generated username, not the phone number.

**Another device on the number dropped off.** Each credential is for one device. Give the PBX its own credential and every other phone or app its own.

**Adding a device fails.** Each number has a device limit. The SIP & Devices tab, and the `active_count` and `limit` fields of the API's list response, show how many are in use. Revoke a device you no longer use to free a slot.

**Outgoing calls fail with the trunk registered.** Check the outbound route and dial pattern, and that your wallet has credit.

## FAQ

### What is a register-based SIP trunk?

A trunk where your PBX signs in to the provider with a username and password, like a phone does, instead of the provider sending calls to a fixed IP address. Because the PBX starts the connection, it does not need a fixed IP address.

### Can I use Sautikit with 3CX?

3CX sells the PBX software but not phone numbers or call minutes; its own headline is "Bring your Own Trunk & Numbers". Sautikit provides the number, using the register-trunk settings on this page, if your 3CX setup accepts a register-based trunk from a provider. See [Sautikit vs 3CX](/compare/3cx) for how costs compare.

### How much does a Sautikit SIP trunk cost?

There is no separate trunk fee. You pay for the number, KES 116 a month including VAT, with no setup fee. Incoming calls are free. Outgoing calls are KES 3.00 a minute, billed per second from when the call connects.

### Do I need a PBX at all?

Not necessarily. A Sautikit number can [forward calls](/developers/guides/forward-calls-and-voicemail) to several phones at once or one after another, with voicemail if nobody answers, and desk phones and softphones can register to it directly.

### Can my PBX show a different caller ID?

No. Outgoing calls show the Sautikit number the trunk belongs to. To show a different number, claim that number on Sautikit and route those calls through its own trunk.

## Staff away from the office

Staff who are not near the PBX can use [SautiKit Phone](/phone), which needs no SIP setup: sign in and the number works. It runs on the [web](https://phone.sautikit.com), [Android](https://play.google.com/store/apps/details?id=com.sautikit.phone) and [Windows](https://apps.microsoft.com/detail/9mxvnklz324k), with iOS and macOS in [beta on TestFlight](https://testflight.apple.com/join/sYaGFBDv).