SIP SMS on a Softphone: Text Customers From Your App
Tom Reed · Updated 31 October 2026
Yes, a business softphone can send texts. SessionTalk's softphone sends and receives SMS through your SIP provider on Android, so staff text customers from the same app they call from. Team chat, group rooms and file sharing sit alongside it. What your provider supports (incoming SMS, delivery reports, MMS) decides the rest.
If you want calling and texting in one place, start with our business softphone with chat, group messaging and SMS built in. This guide explains how SIP SMS works in an SMS VoIP app, how it differs from team chat and file sharing, what your SIP provider needs to support, and how to set up business texting so replies land in the right place.
Can you send SMS from a softphone?
Yes. SMS via SIP lets the softphone send and receive text messages through your SIP provider, so a customer gets a normal text on their mobile and your staff member never has to reach for a personal phone. In the SessionTalk softphone, SMS is available on Android, version 8.0.12 or later. On SessionTalk Free, SMS needs Push and Business.
That's the important detail for planning: softphone SMS is an Android feature today, so if your team texts customers from the softphone, give those people the Android app. Calling, chat, group rooms and file sharing work across the softphone on iOS, Android, Windows and Mac, which keeps the rest of the team in the same conversations even if they don't send customer texts themselves.
The point of a softphone SMS setup is simple. The person who just spoke to a customer can follow up by text from the same app, on the same business identity, without switching to a separate business texting app or a personal mobile number.
What's the difference between SIP SMS, team chat and file sharing?
People often say "messaging" and mean different things. Inside the softphone there are really separate channels, and they run through different places. Our page on SIP messaging and SMS features covers each one in detail.
SMS via SIP goes to customers' mobile numbers and runs through your SIP provider. Whether you see delivery status depends on the provider's service.
Team chat and group rooms are for colleagues inside the app. Chat runs over SIP MESSAGE and the messaging layer, with delivery and read receipts, typing indicators, emoji reactions and group chat rooms with invitations and persistent history.
File sharing sends images, PDFs, documents, audio clips and short video to colleagues in chat conversations, through an authenticated HTTPS upload service. Files show as thumbnails in the conversation, and each file transfer is encrypted end to end with its own key.
SMS vs chat vs file sharing in the softphone
| SMS via SIP | Team chat and group rooms | File sharing | |
|---|---|---|---|
| Who it reaches | Customers' mobile numbers | Colleagues in the app | Colleagues in chat conversations |
| Runs through | Your SIP provider | SIP MESSAGE / messaging layer | Authenticated HTTPS upload service |
| Status shown | Depends on the provider's service | Delivery and read receipts, typing indicators | Thumbnails in the conversation |
| Needs extra provider support | Incoming SMS, delivery reports, MMS | No | No (not carrier MMS) |
| Encryption | TLS signalling in transit | TLS signalling in transit | Per-message end-to-end encryption |
Keep the channels apart in your head and in your rollout. Customer conversations go by SMS. Internal handoffs, questions and "can you take this one?" messages go in team chat or a group room.
What does your SIP provider need to support?
SIP SMS rides on your provider. The softphone sends the message, but the provider carries it to the customer's phone, so the provider's service decides a lot of what you get.
Check these points with your provider before you roll out texting:
- Outbound SMS on your numbers. Not every number or account is enabled for texting.
- Incoming SMS. Receiving customer replies needs separate provider support.
- Delivery reports. Whether you see a delivery status depends on the provider's service.
- MMS. Carrier picture messaging needs separate provider support too.
Images and files shared in chat are a different thing. They use a separate attachment service inside the softphone and are not carrier MMS, so a photo you share with a colleague in chat doesn't mean you can send picture messages to a customer's phone.
One more note for planning: settings for sending SMS through a provider's HTTPS SMS gateway are listed as coming in the next app release. They aren't available yet, so plan around SMS via SIP for now.
Who should text customers from the softphone?
Texting from a softphone suits roles where a short written message saves a call or confirms what was said on one.
- Field staff confirming appointments. An engineer or installer can text "running a little late, with you shortly" from the business app, so the customer sees the company, not a personal mobile.
- Small sales and support teams. After a call, a quick text with the reference or the next step gives the customer something to refer back to.
- Receptionists following up a call. When someone rings and the right person isn't free, the receptionist can call back later or send a short text so the customer knows it's in hand.
If your team already uses a phone system workflow like missed call text back for small businesses, softphone texting is the natural partner: the PBX handles the missed call, and staff pick up the conversation by text from the app. Contact centres weaving text into a wider routing setup should read our guide to SMS in omnichannel contact centres instead.
What doesn't fit: bulk or marketing texts. Softphone SMS is for one-to-one business texting between a staff member and a customer, not campaigns.
How do you set up business texting on a softphone?
Most of the work is agreeing how your team will use it. The technical side is mostly about your provider and getting accounts onto phones cleanly.
Checklist: before your team texts customers
- Confirm your SIP provider supports SMS on your numbers, and whether that includes incoming SMS and delivery reports
- Put the staff who text customers on the Android app (version 8.0.12 or later), and on SessionTalk Free add Push and Business
- Decide which numbers staff text from (main line vs direct lines) so replies come back to the right place
- Provision accounts by QR code so SIP and messaging settings aren't typed by hand
- Turn on push notifications on mobile so replies and calls arrive when the app is closed
- Agree what goes by SMS (confirmations, short follow-ups) and what stays a call
- Use team chat or group rooms for internal handoffs, not customer SMS threads
- Check chat history syncs to staff's desktop and mobile before rollout
- Don't promise MMS to customers unless your provider supports it
For team chat, history follows people between devices: start a conversation on the iOS and Android softphone and carry on from the Windows and Mac desktop softphone. Customer texts themselves are sent from the Android app.
If you also want to see who's free before you message or transfer, our post on phone system presence and team chat covers presence states and how teams use them.
Is softphone messaging secure?
Messaging signalling is encrypted with TLS in transit, and the softphone validates server certificates to prevent man-in-the-middle attacks on messaging connections. File transfers add per-message end-to-end encryption on top, and SIP and messaging credentials are stored using each operating system's protection mechanisms rather than as plaintext.
Be clear about what that means for SMS. Once a text leaves your provider it travels as a normal SMS to the customer's phone, so treat SMS as convenient, not end-to-end encrypted. Keep sensitive details out of customer texts and use a call or a secure channel for anything private.
Pair it with a hosted PBX
Pair it with a hosted PBX so calls and extensions are managed in one place while staff text from the same app: SessionPBX hosted PBX.
SessionPBX gives your business its own SIP domain and short extensions, keeps direct messages, group conversations and file sharing alongside your calls, and lets you set up mobile apps with a QR code or desktop apps with a setup link. SessionPBX doesn't supply numbers or lines: it's a bring-your-own SIP trunk setup, so you connect the SIP trunk you already use and any SIP-compliant carrier works. The softphone also works with SIP-based PBXs, and our PBX phone system explainer covers what a PBX does if you're new to it.
FAQ
Can I text customers from a softphone?
Yes. The SessionTalk softphone sends SMS via SIP through your SIP provider, so customers receive a normal text. SMS in the softphone is available on Android, version 8.0.12 or later, and SessionTalk Free needs Push and Business.
Can I receive SMS replies?
It depends on your provider. Incoming SMS needs separate provider support, so confirm with your SIP provider that replies to your numbers are delivered before you rely on them.
Is chat the same as SMS?
No. Chat is in-app messaging between users, with delivery and read receipts, typing indicators and group rooms. SMS goes to phone numbers through your SIP provider.
Can I send pictures by SMS?
Files shared in chat aren't carrier MMS. They use a separate attachment service for colleagues in the app. Sending picture messages to a customer's phone needs MMS support from your provider.
Does message history follow me between phone and desktop?
Yes for chat. Chat history syncs across the devices you're signed into, so you can start a conversation on your phone and continue it on your desktop. Customer SMS is sent from the Android app.
