Bulk SMS
Bulk SMS for UK businesses
Send one text to a few hundred customers, or to your whole list, from the dashboard or the API. You see the cost before it goes, and anyone who's opted out is left off without you lifting a finger.
What is bulk SMS?
Bulk SMS means sending the same text, or a personalised version of it, to many mobile numbers at once. In CaptiFi Connect you run a campaign: choose a list, write the message with merge fields like {first_name}, check the part and credit count, then send now or schedule it. Only UK mobiles are accepted, and opted-out numbers are refused without charge.
How bulk sending works in CaptiFi Connect
To text a whole list, run a campaign. Give it a name, choose the list, write the text, then send it now or schedule it. Its row on the Campaigns page shows progress and delivery counts while it goes out, and you can cancel it before it's sent. Send SMS is the quick option for a one-off to a handful of people, with numbers you type or paste in.
Whichever you use, the composer counts as you type. You get the characters, how many parts the text will split into and the credits the whole send will take, and it flags any character that would switch the message to Unicode (a curly apostrophe pasted in from a Word document is the usual culprit).
Every number is checked before anything's charged. Landlines, numbers outside the UK, duplicates within the same send and anyone on your opt-out list are taken out and listed with a reason, so you can see who was skipped and why, and none of them cost a credit.
What you can do with it
All of this is in the dashboard now:
- Personalise each text with merge fields ({first_name}, {last_name}, {full_name}, {phone} and {email}), filled in from each contact.
- Import contacts from a CSV, map its columns to fields and drop everyone into a list in one go. Numbers you already have are updated in place, and you get a report of any rows that were skipped.
- Save the texts you send often as templates.
- Schedule a send up to a year ahead, and cancel it before it goes to get the credits back.
- Send from an approved sender name, such as your business name, so people know who it's from.
- Find every text in message history, filter it by status or campaign and export it as CSV.
Rules and limits that apply
CaptiFi Connect texts UK mobile numbers only, including numbers in Guernsey, Jersey and the Isle of Man. Landlines and numbers in other countries are refused with a reason and aren't charged.
A single text can run to 10 parts. In the standard GSM-7 character set that's 160 characters in one part, or 153 per part once it splits; in Unicode it's 70, then 67 per part. One credit covers one part to one UK mobile, so a two-part text to 500 people uses 1,000 credits.
Campaigns, and anything sent from a sender name, go through a licensed A2P (application-to-person) route, the kind built for business texts sent by software at volume. We check every new account before it can send. Test API keys work in the meantime, so you can get set up while you wait.
If the list is for marketing, UK law asks for consent or a soft opt-in, plus a way to opt out in every message. Campaigns add your opt-out line ('Reply STOP to opt out' unless you change it), and STOP replies are dealt with automatically. Our guide to the UK rules for marketing texts covers the rest.
For developers
To text a whole list from your own code, create a campaign with POST /api/v1/campaigns (a name, a list_id, the body and an optional sender) and start it with POST /api/v1/campaigns/{id}/send. POST /api/v1/messages is for one-to-one texts and small batches. It takes numbers in to, or contact_ids, along with the body and an optional sender, and returns the messages it created and a rejected list for the numbers it refused, each with a reason code such as not_mobile or opted_out.
Send an Idempotency-Key header with every POST /api/v1/messages. If a request times out and you retry it with the same key, the batch won't go out twice. Want the cost first? POST /api/v1/messages/quote gives you the encoding, parts and credits without sending anything.
Delivery updates arrive as message.sent, message.delivered and message.failed webhook events, signed with HMAC SHA-256 so you can check they came from us.
Send a bulk text, start to finish
- 1
Import your contacts
Upload a CSV, match its columns to names, numbers and emails, and add everyone to a list.
- 2
Write the text
Drop in merge fields where you want them and keep an eye on the part count as you go.
- 3
Pick a sender name
Choose an approved sender name if you have one, so the text arrives under your business name.
- 4
Check the cost
The composer shows the credits the send will use before you confirm anything.
- 5
Send or schedule
Send it now or choose a time up to a year ahead, then follow progress on the Campaigns page.
How many characters fit in a text
| Character set | One part | Each part once split | Ten parts, the most a text can use |
|---|---|---|---|
| GSM-7: standard letters, numbers and common symbols | 160 | 153 | 1,530 |
| Unicode: emoji, curly quotes and some accented letters | 70 | 67 | 670 |
Questions people ask
Do I pay for numbers that are refused?
No. Landlines, numbers outside the UK, duplicates and opted-out numbers are refused before sending and never charged. A text that fails before it leaves us is refunded too. What isn't refunded is a text the network tried to deliver and couldn't, because it did go out.
Can I send bulk SMS under my business name?
Yes, once the name is approved. Sender names are 3 to 11 characters with at least one letter, and our team checks each request, including against the MEF SenderID Protection Registry. People can't reply to a text from a name, so it suits one-way messages.
How much does bulk SMS cost?
You buy credits up front, and one credit covers one SMS part to a UK mobile. Replies are free. Packs run from £25 for 500 credits (5p a text) to £700 for 20,000 (3.5p), plus VAT, and credits never expire. The full table is on the pricing page.
Can I send bulk texts to numbers outside the UK?
No. CaptiFi Connect only texts UK mobiles, including Guernsey, Jersey and the Isle of Man. Anything else is refused with a reason and costs nothing.
Will people who've opted out get my campaign?
No. Anyone who's texted STOP (or one of the other opt-out words) is on your opt-out list, and sends to them are refused at the point of sending, free of charge.
Can I try it before my account is approved?
Yes, with a test API key. Test sends go nowhere and cost nothing, but they behave like real ones: each text is marked sent, then delivered a few seconds later, and the sent and delivered webhooks fire. Test keys are capped at 50 numbers a request and 300 numbers an hour.
Can I send pictures or links?
Links, yes, typed into the text like any other words. Pictures, no: CaptiFi Connect sends SMS text messages only.
Send your first text this week
Set up your account and contacts now; we check every new account before it can send.