Real cellular SMS. On the business number.
Two-way SMS and MMS on a real US cellular number — A2P 10DLC pre-registered for business-volume deliverability. Send and receive photos, video, documents up to standard MMS limits. Group threads supported. Saved replies, scheduled sends. Banks, payment platforms, and government services accept the number for 2FA SMS the same way they accept a personal cell.
SMS & MMS on Kelir.
Kelir SMS is two-way text messaging on the business number — same primitive every UCaaS vendor ships, with two key differences. First, the number is a real US cellular number with native SMS, not a virtual VoIP number. Second, the number is pre-registered through The Campaign Registry for A2P 10DLC, which means business-volume SMS gets through carrier filters that increasingly block unregistered virtual numbers.
A2P 10DLC ("Application-to-Person 10-Digit Long Code") is the US carrier framework for business SMS. As of 2024–2026, US carriers (Verizon, T-Mobile, AT&T) require A2P 10DLC registration for any business sending more than incidental SMS — appointment reminders, transactional confirmations, two-way customer messaging. Unregistered traffic gets filtered, blocked, or labeled as spam. Kelir handles brand registration with The Campaign Registry on every Kelir line, so customers don't have to navigate the registration process themselves.
MMS (Multimedia Messaging Service) is the photo, video, and document version of SMS. Kelir supports MMS for sending and receiving images and short video clips up to standard MMS size limits (~1 MB on most US carriers; some support up to 5 MB via business messaging fallbacks). Useful for contractor quote photos, clinic appointment confirmations with location maps, agency contract PDFs, retail product images.
Group SMS threads are supported — start a thread with multiple recipients, everyone sees replies. iMessage interop on iPhones works the way it would for a personal cellular line; Android and iPhone interop uses standard MMS group messaging. RCS (Rich Communication Services) interop where carriers and devices support it.
Saved replies and scheduled sends are productivity additions. Save common responses ("Confirmed for Tuesday at 2pm"), insert with one tap. Schedule a send for 9 am tomorrow morning to land in the recipient's inbox at the right time. On Team plans, a shared template library lets the whole team use vetted, approved replies.
Setup walkthrough.
Configured from Mobile app. The setup below assumes a working Kelir account and an active eSIM.
- 1
Open the Kelir mobile app and tap the Messages tab.
- 2
Tap New message. Enter recipient(s) by phone number or pick from contacts.
- 3
Type the message. Attach a photo, video, document, or location from the attachments menu.
- 4
Send. Threads persist in the Messages tab, sorted by most recent.
- 5
On iOS, opt in to Business Messages integration so Kelir messages appear in the iOS Messages app alongside personal SMS.
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Save common replies: long-press a sent message → Save as template. Tap the templates icon during composition to insert.
- 7
Schedule a send: tap the clock icon during composition → pick a future date/time. The message queues and sends automatically at that time.
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Group threads: add multiple recipients to a single message; replies broadcast to the group.
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On Team plans, admins can populate a shared template library at app.kelir.io → Settings → Templates. Members see shared templates alongside personal saved replies.
Where sms & mms earns its keep.
Appointment reminders
"Hi, this is Sarah from Reeves Construction — confirming we're scheduled for Tuesday 9am at your address." Sent the day before. Two-way thread lets the customer reschedule by reply.
Quote photos for contractors
Customer texts: "Can you take a look at this leaky pipe?" Sends a photo. Contractor reviews the photo from the lock screen, replies with a quote and availability — all on the business cellular number, MMS standard.
2FA SMS codes for client portals
Customers add Kelir number to bank, MLS, lender platform 2FA. Real cellular number = codes always arrive. Replaces the rejected-as-virtual problem common with VoIP business numbers.
Multi-recipient client thread
Real-estate agent loops in the buyer, the seller, and the title company in a single SMS thread for closing-week coordination. Group thread; everyone sees the same updates.
Scheduled morning send
Schedule a Sunday-evening send for Monday 9am to follow up with prospects from the previous week. Lands in their inbox during the work-day, not late Sunday.
The same feature.A real cellular line.
SMS is universal in UCaaS, but the deliverability story varies dramatically. Kelir's number is real US cellular with A2P 10DLC; many softphone competitors run on virtual numbers that increasingly get filtered.
- Real US cellular number — accepted for 2FA SMS by banks, Stripe, MLS, government, and other services that increasingly block VoIP virtual numbers.
- A2P 10DLC pre-registered through The Campaign Registry. Customer doesn't navigate the registration process; brand is approved at signup.
- Native MMS — photos, video, documents — through standard cellular MMS rather than a softphone-app fallback that may render media as links.
- Standard SMS group threads supported across iPhone and Android; iMessage interop on iPhone-to-iPhone the way personal cellular numbers work.
- Lock-screen previews and read-status work via iOS Business Messages integration on iPhone.
- Throughput limits scale with A2P 10DLC tier — Solo and Team Starter at standard rates, Team Pro raised throughput on request for high-volume use cases.
Common questions
Yes. Every Kelir line is pre-registered with The Campaign Registry under Kelir's brand. Customers don't navigate the carrier-by-carrier registration process. The pre-registration covers transactional and conversational use cases (appointment reminders, customer confirmations, two-way support). Marketing-volume SMS may require additional campaign registration; engage support if your volume is unusually high.
US carriers (Verizon, T-Mobile, AT&T) increasingly filter SMS from unregistered business numbers — VoIP virtual numbers in particular get blocked or labeled as spam. A2P 10DLC registration tells the carriers "this is a legitimate business sending legitimate SMS". Without it, your messages may not reach customers; with it, deliverability matches a registered enterprise sender.
Yes. Because the Kelir number is a real US cellular number with native SMS, services that send 2FA codes (banks, payment platforms, government services) deliver to it the same way they deliver to a personal cellular line. This is one of the practical benefits of cellular delivery vs softphone-VoIP.
Standard cellular MMS is ~1 MB on US carriers. Larger media (up to 5 MB) sometimes succeeds via business-messaging fallbacks but isn't guaranteed across all destination carriers. For larger files, consider sharing a link to a hosted file (cloud storage, etc.).
Yes. Add multiple recipients to a single message. Replies broadcast to the group; everyone sees responses. iMessage between iPhone users renders as iMessage groups (blue bubbles); cross-platform groups (iPhone + Android) use standard MMS group messaging (green bubbles).
Both. The Kelir mobile app has a Messages tab with full SMS/MMS UI — composing, threading, scheduled sends, saved templates. On iOS, Business Messages integration makes Kelir messages also appear in the iOS Messages app alongside personal SMS, so you can answer either way. Threads are kept in sync.