SIP Trunking

MessageBird's SIP Trunking allows you the possibility to place outbound voice calls from your VoIP platform to phones anywhere in the world.

A SIP-trunk makes calls via the public internet or a private IP-connection. Our SIP-trunks run authentication protocols on your IP-addresses and/or a username-password combination. In this quickstart, you'll learn how to set up accepting inbound SIP-calls. Keep in mind that it's currently not possible to SIP-register with MessageBird.

How to set up SIP trunking:

To start making outbound calls, you need to authenticate your VoIP platform. The easiest way is to add the IP address of your VoIP platform in your MessageBird Dashboard.

Select SIP Trunking on the 'Voice' icon in the left-panel menu, hit 'Add new', and fill in your details.

Step 1: Add an ACL (Access Control List)

An ACL is used to define which IP-addresses and/or username-password accounts are allowed to use yours. To manage the authentication of your VoIP infrastructure, you can create multiple ACLs, each with one or more accounts.

Click on 'Access Control' and hit the 'Add New' button. Name each ACL in a new pop-up window so you can easily recognize them. After saving the ACL, it will appear in the overview.

When you click the ACL name, you'll see a new screen where you can add IP-addresses and/or username-password accounts. The options are:

  • IP-address
  • Username/password
  • IP-address and a combination of username/password.

If you have entered both an IP-address and a username/password, both need to be used in the SIP-INVITE header.

This is an example of a FROM field as part of SIP-INVITE header with username 31000000:

  • SIP from address: sip:31000000@[yourdomain];transport=UDP

Step 2: Add a Subdomain

A subdomain is a personal DNS name inside the domain, for example, Only calls to this specific subdomain will be authenticated by the attached ACL’s.

To add a subdomain, go to 'SIP Trunks', hit the 'Add new' button. You'll see a pop-up screen where you can insert your subdomain name.

The field 'Domain' is the address used for your SIP-communication. A valid domain name contains:

  • Minimum of 1 character
  • Valid characters range from 0-9, a-z and A-Z

After creating a Domain, you can attach an ACL to this Domain by selecting the domain in the left-hand menu and clicking on 'Attach Access Control List'. Choose the preferred ACL to attach to this domain and save your choice.

On the SIP Trunks page, you’ll find an overview of the ACLs attached to this particular domain. Keep in mind that a domain can have multiple attached ACLs and an ACL can be attached to multiple domains

That's it! 🎉

You're all ready to place calls from your VoIP platform to our SIP servers.

Remember that only accounts attached to this domain can place calls, so the full domain name should be used in the SIP-INVITE header.

This is an example of a SIP-INVITE header:

  • sip:[your_account]@[your_domain]

Localisation (optional)

For customers that require localised SIP trunking we are available in 3 regions: Asia, Europe, US.

By using the default configuration of [your_domain] your traffic will be redirected to our European servers or, in the case of a local failure, to one of the 3 available regions. To be able to keep your traffic bound to one region and avoid an additional hop through our European servers, you can configure the domain name as follows:

  • Asia: [your_domain] [your_domain]

  • USA: [your_domain] [your_domain]

  • EU: [your_domain] [your_domain] By using these subdomains inter-region failover is not guaranteed.

What's next?

You may now want to check out these resources:


We’re always happy to help with code or other doubts you might have! Check out our Quickstarts, API Reference, Tutorials, SDKs, or contact our Support team.

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