Back in stock alert texts that customers ask for

A sold-out size with a box underneath that says "Text me when it's back" is about the friendliest piece of marketing a shop can run. The customer chose the item, typed their own number and asked for one specific message. Back in stock alert texts are the rare case where the person on the other end is waiting for you to get in touch, and the wording should treat that request with some care, because it's narrower than it looks.

Our post on click and collect, stock and sale texts covers where these sit among a shop's other texts. This one is about the request itself: what the sign-up box should say, what the alert should say, how long to hold on to a number, and what to do when two hundred people asked and forty coats came in.

Why a requested alert is different

PECR's consent rule for marketing texts, regulation 22, opens by saying it "applies to the transmission of unsolicited communications by means of electronic mail to individual subscribers". The ICO's guidance draws the line in one sentence: "Electronic mail marketing is solicited when someone specifically asks you to send a particular message or type of information. All other electronic mail marketing is unsolicited."

Its example is a brochure. Somebody asks for your summer brochure, and "Sending that brochure is solicited marketing because they specifically requested it." Then the second half: "Later, you email them again about a new offer. They did not ask for that specific email, so it is unsolicited marketing."

A back in stock alert is the brochure. The request covers that message, about that item, and nothing after it.

One rule still applies to it. Regulation 23 of PECR covers every "communication for the purposes of direct marketing by means of electronic mail", solicited or not, and forbids sending one where the sender's identity is "disguised or concealed" or where "a valid address to which the recipient of the communication may send a request that such communications cease has not been provided". So the alert names the shop and carries a way to say stop, even though nobody needed to consent to it. The ICO makes the same point about consent in its guidance on valid consent, with a business card dropped into a prize draw box: the act "clearly indicates they agree to their name and contact number being processed for the purposes of the prize draw", but "this consent does not extend to using those details for marketing or any other purpose". Swap the business card for a phone number and the prize draw for a restock, and you have the rule for the alert.

The sign-up box

The box is where the request is defined, so it should say exactly what the customer is asking for. Four things belong in it: the item and variant, the fact that it's one text, how long you'll keep the request, and (only if you want it) a separate choice about marketing.

Text me when the Harris coat in navy, size 12, is back. One text, only about this coat. We'll delete your number after we text you, or after 90 days if it doesn't come back.

[ ] Also send me texts about new arrivals and offers. You can reply STOP at any time.

Naming the size and colour stops the alert going out when a different size arrives, which is a fast way to lose the customer's goodwill. "One text, only about this coat" is the scope, written so the customer knows it and you're held to it. The deletion line is the storage rule in plain words, covered below.

The second box is the marketing question, and the ICO's consent guidance decides how it looks. "You may not rely on silence, inactivity, default settings, pre-ticked boxes or your general terms and conditions". It has to start unticked, and it has to be separate: the guidance says consent "should be unbundled from other terms and conditions" and that a request "needs to be prominent, concise, separate from other terms and conditions, and in plain language". A customer who wants the coat and nothing else should be able to get the coat alert without ticking anything. Our post on writing a consent request that stands up has the records to keep.

Could the request start the soft opt-in instead, so you can market without the second box? Perhaps. The ICO's own example of an enquiry that "could constitute negotiations for a sale" is a customer asking "if the company can order a particular product", which is close to a restock request. But the soft opt-in also needs a simple chance to opt out shown at the moment you collect the number, and the second box above does that job anyway. Tick-to-consent is the cleaner record, so we'd use it.

A confirmation, if you send one

A text straight after sign-up is optional, and useful. It proves the number works, it tells the customer the request landed, and it gives them a way to cancel. It confirms something they asked for and promotes nothing, so it's a service message.

Hollin & Reed: you're on the list for the Harris coat, navy, size 12. We'll text once when it's back. Reply STOP to cancel.

Keep it to that. A confirmation that adds "and here's 10% off while you wait" has become a marketing text sent to someone who asked for something else.

The alert itself

The alert is the text the customer asked for, so it should be instantly recognisable as that text. Business name first, the exact item, a link to it, and something honest about quantity if quantity is short.

Hollin & Reed: the Harris coat in navy, size 12 is back in stock. example.co.uk/p/4k2 It's our only text about it. Reply STOP to opt out

That's 136 characters, so one SMS part with a little room for a merge field such as the first name. "Our only text about it" tells the customer the request is now used up, and the STOP line is the regulation 23 address in the form people know. If you'd like to be able to see whether people tapped through, a tracked short link reports each click; our link tracking page says what the report contains.

Things to leave out: anything else you're selling, and urgency that isn't real. "Selling fast" and "only 3 left" are claims, and our post on prices in promotional texts covers why a shop needs to be able to back them up.

When there isn't enough to go round

Restocks are often smaller than the waiting list. You have two fair options, and the wording follows from the choice.

Send in the order people asked, in batches sized to the stock, and stop when it's gone. The customers who signed up first get the coat, and nobody gets a text for stock that no longer exists. If a batch sells out before the next, send the rest a short apology, which is a service message about their request:

Hollin & Reed: sorry, the size 12 Harris coats we got in have all gone. We'll keep your request until 30 Jan and text if more arrive.

Or text everybody at once and say so in the alert ("20 in this batch"), so the person who taps through an hour later and finds it gone wasn't misled. What isn't fair is texting two hundred people about forty coats with no hint that most of them will miss out.

How long to keep a request

Article 5(1)(e) of the UK GDPR says personal data must be "kept in a form which permits identification of data subjects for no longer than is necessary for the purposes for which the personal data are processed". The ICO's guidance turns that into practice: a policy with "standard retention periods wherever possible", and a habit to "periodically review the data you hold, and erase or anonymise it when you no longer need it".

For a back in stock request the purpose has a natural end. Once the alert has gone, the number has done its job unless the customer also ticked the marketing box, so delete it. If the item never comes back, set a limit (90 days seems about right for seasonal stock, and longer suits a product you know is on order) and say what it is on the form. Data minimisation, article 5(1)(c), points the same way: "adequate, relevant and limited to what is necessary". A mobile number and the product variant are enough. A name helps the wording. A date of birth doesn't belong anywhere near it.

Online sales are a big enough share of most non-food retail that these requests pile up. The ONS put internet sales at 27.0% of clothing and footwear stores' sales in September 2026, and 28.8% for household goods stores, up from 12.5% and 10.3% in September 2016.

Setting it up

From a website, the simplest version is one API call per request when the stock lands: POST /messages with the number and the text, plus an Idempotency-Key made from the request id so that a stock update processed twice can't text anyone twice. Send in batches if stock is short, as above, and delete each request once its message is accepted.

In a shop, a keyword does the same job without a website. Put "Text COAT12 to 07700 900456" on the shelf edge, and a keyword on a dedicated number can send an automatic confirmation and add the sender to a list for that item. When the coats arrive, send to the list. Either way, a STOP reply puts the number on the account's opt-out list, and later sends to it are refused.

Common questions

Do I need consent to send a back in stock text?

Not for the alert the customer asked for. The ICO treats marketing someone specifically requested as solicited, and PECR's consent rule applies to unsolicited messages. Anything you send afterwards that they didn't ask for is unsolicited and needs consent or the soft opt-in.

Can I use back in stock sign-ups for my marketing list?

Only the people who also ticked an unticked box agreeing to marketing texts, or who otherwise meet the soft opt-in conditions, including a clear opt-out offered when the number was taken. The ICO's guidance says pre-ticked boxes and silence are not consent.

How long should I keep a back in stock request?

Until the alert is sent, or until a limit you've stated on the form if the item doesn't return. The UK GDPR says personal data should be kept no longer than necessary, and a request has a clear end point.

Should a back in stock text say Reply STOP?

Yes. Even a requested alert is direct marketing, and regulation 23 of PECR forbids sending direct marketing by text without a valid address the recipient can use to ask for it to stop. "Reply STOP to opt out" on a number that takes replies does that.