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Telephony

Bringing your own number

Porting or pointing a number you already own.

Two ways to keep a number you already own

If the number already exists with another provider (Twilio, Plivo, your own PBX), you have two options. They are not interchangeable.

PortingSIP trunking
OwnershipTransfers to FinnStays with your provider
Your old provider billEndsContinues
Time to working5-15 business daysSame day
ReversibleOnly by porting out againYes, remove the trunk
Best forNumbers you want Finn to own outrightExisting telephony investment you are not replacing

Both are configured in the dashboard. There is no API endpoint for starting a port or creating a trunk. The phone numbers API reads and assigns numbers that already exist in your inventory, so you cannot script either of these flows.

Porting a number in

Porting is a real ownership transfer. The losing carrier hands the number over and stops billing you.

  1. Go to Settings → Phone numbers → Port a Number.
  2. Upload the LOA (Letter of Authorization) and a recent bill from your current carrier.
  3. Submit.

The port takes 5-15 business days depending on country. What goes wrong, in rough order of frequency:

  • The bill and the LOA disagree. The account holder name, service address, and account number on the LOA must match the carrier's records character for character, not approximately. A mismatch is rejected, and the rejection arrives days later.
  • The bill is stale. Provide the most recent one. Older bills may not reflect the current account state at the losing carrier.
  • You release the number early. Do not cancel service with your old provider to "speed things up." Cancelling before the port completes can send the number back into the carrier's pool, and once that happens you may not get it back.

Keep the number live on your existing provider until the port completes. Traffic continues to arrive there until cutover.

SIP trunking instead

If you want calls answered by Finn today, or the number must stay where it is for contractual reasons, trunk it.

  1. Go to Settings → Telephony Account → Add SIP Trunk.
  2. Enter your provider's SIP endpoint, credentials, and supported codecs.
  3. Configure inbound routing: which Finn answers calls arriving on which DID.

The codec list is the part people get wrong. If your trunk and Finn do not agree on a codec, the call connects and then sits in silence for 5-10 seconds before anything happens, which callers read as a broken line. Check your trunk configuration against the codecs you declared. See BYOC and SIP for the full trunk reference.

SIP trunking suits enterprise setups with existing telephony. If you have no existing PBX, porting is simpler to operate long term.

After the number arrives

A ported or trunked number is not automatically ready for production traffic.

Check capabilities. Voice inbound, voice outbound, and SMS are separate capabilities and a ported number does not necessarily carry all of them. See number capabilities.

Assign a Finn for inbound. Until you set a default inbound Finn, or a routing rule that resolves to one, inbound calls go straight to voicemail. Set it under Settings → Phone numbers → [Number] → Default Inbound Finn, or build rules in inbound routing.

Register caller ID if you are dialing US or Canada. STIR/SHAKEN attestation is handled for you. CNAM and brand registration are not. Submit them under Settings → Phone numbers → [Number] → Caller ID Registration. Carrier review takes 1-3 weeks. An unregistered high-volume number gets labeled "SPAM LIKELY" and answer rates collapse. See caller ID and spam labeling.

Start the registration as soon as the port completes. The 1-3 week review is the long pole in going live, not the port itself.

Check compliance status per country. Regulated countries may require KYC or business verification before the number can originate calls. If calls to one country fail while another country works, look at Settings → Phone numbers → [Number] → Compliance Status.

Porting out

You can port a number away from Finn to another carrier. Do this rather than releasing a number you care about. Released numbers leave your inventory immediately and generally cannot be recovered, and released US and Canada numbers sit in a 30-day quarantine before reassignment.

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