Phone numbers
Connect numbers through Twilio, Telnyx or your own SIP trunk, decide what each is for, and set how many calls it may carry at once.
A phone number is where calls come in and where outbound calls come from. Numbers live in your workspace and are assigned to flows and agents.
Where numbers come from
- Twilio or Telnyx — connect an account and use its numbers.
- Your own carrier — bring numbers in over a SIP trunk, keeping your existing provider and contracts.
Numbers can also be listed, provisioned, updated and released over the API — see Account & numbers.
What a number is for
Each number has a purpose: inbound, outbound, or both. Outbound calls and campaigns pick their caller ID from the numbers allowed to call out.
Concurrency
Concurrency is how many calls a number may carry at the same time. Each number has a default, which can be raised up to a platform maximum. Separating numbers by purpose keeps an outbound campaign from using up the lines your inbound calls need.
The maximum is enforced
A value above the platform maximum is rejected, not quietly accepted. Workspace-wide capacity is set by your concurrency lines — see Concurrency and limits.
More than voice
A number can also carry SMS and WhatsApp, and can be used from the browser softphone by your own team. See Messaging channels.