Buying Phone Numbers
Before you can send SMS, you need at least one phone number associated with your account. Buy them at Numbers → Buy. Manage existing inventory at Numbers → Manage.
Search
- Open Numbers → Buy.
- Filter by:
- Country — US is the default; other countries depend on carrier inventory.
- Number type — local, toll-free, or mobile (where available).
- Area code for local numbers.
- Pattern — find numbers that start with, end with, or contain a digit string (great for vanity numbers).
- Capabilities — SMS, MMS, or SMS+MMS.
- Click Search. We return current inventory from our carrier partners.
Number types
| Type | Use case |
|---|---|
| Local long code | Transactional and conversational SMS via 10DLC |
| Toll-free | Higher-volume notifications and support; requires toll-free verification before unthrottled sending |
| Mobile (intl) | Two-way SMS in markets that allow it |
Purchase
Click Buy next to a number. The monthly fee charges against your balance immediately (see Topping Up Your Account Balance). The number is provisioned in seconds and appears at Numbers → Manage.
If your balance is too low, the dashboard prompts you to top up first.
Compliance steps after purchase
Local US long codes must be:
- Attached to a 10DLC campaign — see Creating a 10DLC Campaign. Without this, US application traffic is filtered or blocked.
- Assigned to a messaging profile — see Creating a Messaging Profile. Without this, inbound webhooks have nowhere to fire.
Toll-free numbers must go through toll-free verification before unthrottled sending — submit it from the number's detail page in Numbers → Manage. Until verified, you can send a limited daily volume.
Capabilities
A number's capabilities (SMS, MMS, or SMS+MMS) are set by the carrier and shown in the search results. You can't add capabilities after purchase — pick a number with the capabilities you need.
| Capability | What it enables |
|---|---|
| SMS | Send and receive text messages |
| MMS | Send and receive media (images, audio, vCard) |
International MMS support is limited; check the country page in the API docs at api.otterblocx.com/docs.
Bulk buying
For larger inventories, search and buy from Numbers → Buy: the search supports filters for country, area code, capabilities, and pattern, then lets you add multiple numbers to a cart and check out in one go.
Releasing a number
You can release from the manage page. Releasing is permanent:
- The number returns to the carrier pool and cannot be recovered.
- Monthly fees stop on release.
- All inbound messages and calls to a released number are dropped silently.
We require typing the last four digits to confirm release as a safety check.
Cost
Monthly fees vary by country and number type. The price is shown next to each number in the search results before you buy. Inbound and outbound messaging is charged separately per segment — see your plan at Billing → Plans.