Before you can send an SMS or place a call, you need a phone number attached to K3X. Two paths:
Buy a fresh number from K3X — fastest, you're live in a couple of minutes.
Port an existing number from another provider — keep the number your customers already know; takes 1–2 weeks end-to-end.
Path 1: Buy a number.
Open Settings → Phone Numbers → Add number. K3X asks for three things:
Country — most teams start with the US or Canada.
Number type — see the breakdown below.
Area code or pattern — e.g. 415 for San Francisco, or leave blank for any available.
Pick one from the list, click Buy, and the number is yours. Numbers cost $1.15/mo per number (local or toll-free) plus a one-time $1.15 setup fee — billed alongside your K3X subscription. After the purchase, K3X drops you into the number's configuration page where you assign it to a user (or to round-robin across the team), set a voicemail greeting, and set business hours.
Number types at a glance.
Local (e.g. +1 415 555 0100) — best for outbound calling and one-to-one sales SMS. Requires A2P 10DLC registration before you can send US/Canada SMS at scale. See the A2P 10DLC compliance guide.
Toll-free (e.g. +1 855 555 0100) — looks like a business number, higher trust, but requires Toll-Free Verification (TFV) before sending SMS to US/Canada. Different (often simpler) registration path than 10DLC. See the TFV article.
Short code (e.g. 62425) — 5-6 digit numbers, very high throughput, mostly for marketing blasts. Months to provision, $1000+/mo, requires K3X support to set up. Most teams don't need one.
Path 2: Port an existing number.
If you already have a business number with another carrier (RingCentral, Dialpad, your old VoIP, even a desk phone line), you can move it to K3X without losing it.
Open Settings → Phone Numbers → Port a number. K3X collects four things from you:
The number(s) you want to port.
A copy of your most recent bill from the current carrier (PDF or screenshot) — used to verify ownership and account details.
A signed Letter of Authorization (LOA) — K3X generates this from the number, your business name, and the account details. You countersign in the browser.
The desired port date (default: next business day after approval).
Submit, and K3X takes it from there. Expect this timeline:
1–2 business days — K3X submits to the carrier and confirms paperwork is clean.
5–7 business days — your losing carrier processes the release.
Port date — the number cuts over to K3X. Calls and texts go to your old carrier until the cut-over, then to K3X.
You'll get a status email at each step. Most ports complete in 7–10 business days; complex ones (multiple numbers, legacy carriers) can take 2–3 weeks.
Things to know.
Don't cancel your old carrier service before the port completes — if the number is released early, the port fails.
Toll-free verification doesn't transfer. If you port a toll-free number that was already verified elsewhere, you'll need to re-submit TFV in K3X. Submit it the day the port completes to minimize downtime.
A2P 10DLC registration is your business's, not the number's. Once your business is registered, any local US/Canada number you buy or port can be added to your A2P campaign.
Porting fee is $15 per number, billed once on completion.
You can release a number back into the pool from Settings → Phone Numbers → [number] → Release. Releases are permanent — you can't get the same number back.
Next: Send your first SMS from K3X →
