Two-way SMS
Two-way SMS on a real UK mobile number
Text a customer and they can text you back. Replies to your texts come back to your inbox, threaded by number, and when you answer, it goes from the number they texted whenever that number's available.
What is two-way SMS?
Two-way SMS lets people reply to a business text and get an answer back. In CaptiFi Connect your one-to-one texts go from a real UK mobile number, replies arrive in an inbox threaded by number, and you answer from the number they texted whenever it's available. Receiving replies is free, and each one can be posted to your own system by webhook.
How two-way texting works in CaptiFi Connect
Texts you send one to one, from Send SMS or the API without a sender name, go out from a real UK mobile number, so when someone replies, the reply comes back to us and lands in your inbox. Each thread is one phone number, newest at the top, with your texts and theirs in order. Answer from the thread and your reply goes from the same number whenever that number's available, since a conversation that hops between numbers looks a bit odd to the person on the other end.
Every reply is in message history too, with the rest of your texts, and the home page counts replies for the last 7, 30 or 90 days.
Replies cost nothing. You only pay for the texts you send, at one credit per part.
What you can do in the inbox
The inbox is built for answering people, so it stays simple:
- Read every conversation threaded by number, with unread counts so you can see what still needs an answer.
- Reply from the thread, and the text goes from the number the customer texted whenever that number's available.
- Search message history for a number or a word, and open the timeline of any text.
- Let opt-outs look after themselves: a reply of STOP or one of the other opt-out words adds the number to your opt-out list without you doing anything.
- Export inbound and outbound texts from message history as a CSV when you need a record.
Rules and limits that apply
Replies only work when there is a number to reply to. A text sent from a sender name (your business name, say) cannot be answered, so keep sender names for one-way messages and use two-way texting for anything you want a response to.
Two-way texting covers UK mobiles only, including Guernsey, Jersey and the Isle of Man. If someone replies with STOP, STOPALL, STOP ALL, UNSUBSCRIBE, CANCEL, END, QUIT, OPTOUT or OPT OUT as the whole message, in any case, they go on your opt-out list, and anything you'd scheduled to them is cancelled and refunded. START or UNSTOP takes them off again.
Big campaigns to a list travel a different way, through a licensed A2P route set up for volume. Two-way texting is for conversations with your customers. Nothing in the inbox replies on its own either: CaptiFi Connect doesn't send automatic replies, so every answer in a thread is one you or your system chose to send.
For developers
Each reply fires a message.received webhook with the message in the payload, signed with HMAC SHA-256, so your CRM or booking system can pick it up as soon as it arrives. To answer, call POST /api/v1/messages with the customer's number in to. GET /api/v1/conversations lists threads newest first with unread counts, GET /api/v1/conversations/{phone} returns one thread, and POST /api/v1/conversations/{phone}/read marks its replies as read.
STOP replies come through as opt_out.created, which is the event to wire into your own suppression list. Test keys simulate the outbound side (sent, then delivered a few seconds later) at no cost. They never produce message.received or opt_out.created, so try your reply handling with a live key and your own phone once your account's approved.
Start a conversation
- 1
Send the first text
From Send SMS in the dashboard, or with POST /api/v1/messages.
- 2
Get the reply
It shows up in the inbox, threaded under that number, and in message history.
- 3
Answer from the thread
Your reply goes from the same number whenever it's available, so the conversation stays in one thread.
- 4
Pass it to your systems
Point a webhook at your CRM or helpdesk to receive message.received events as they happen.
Questions people ask
Is receiving SMS replies free?
Yes. Replies don't use credits. You pay one credit per part for the texts you send, and nothing for the ones you get back.
Can customers reply to a text sent from my business name?
No. A sender name has no number behind it, so phones can't reply to it. Use two-way texting, which sends from a real UK mobile number, for anything you want answers to.
Can I receive replies in my own system?
Yes. Add a webhook and subscribe it to message.received. Each delivery is signed with HMAC SHA-256, retried if your endpoint doesn't answer with a 2xx within 8 seconds, and carries a delivery ID you can use to drop duplicates.
What happens if someone replies STOP?
Their number goes on your opt-out list, any pending texts to them are cancelled and refunded, and later sends to them are refused without charge. If they text START or UNSTOP, they come off the list.
Can I start a conversation from the API and carry it on in the dashboard?
Yes. Threads are grouped by phone number, whatever sent the text, so a reminder your booking system sends through the API and the reply that comes back sit in the same thread in the inbox.
Can my whole team use the inbox?
Team members with their own logins and roles are coming, but they aren't available yet.
Which numbers can I text?
UK mobiles only, including Guernsey, Jersey and the Isle of Man. Landlines can't receive our texts, so they're refused before sending with no charge.
Send your first text this week
Set up your account and contacts now; we check every new account before it can send.