Receive and act on messages sent to UK numbers

The UK has no single inbound number type, and that is the first thing to be clear about. The choice depends on what the number is for, how much traffic you expect and whether the same number must also send. The realistic options are virtual and dedicated long numbers, Ofcom-allocated short codes, and SIM hosting on an ordinary mobile number. Each carries a different public-facing identity, a different cost profile and a different provisioning path, and choosing badly means paying for capacity you do not use or running out of it.

The receiving side matters because inbound traffic is not a technology afterthought in the UK: reply strings, opt-in and opt-out keywords and customer replies all arrive on a number, and they arrive as data your systems must be able to ingest. WorldText hands every inbound message to your application over webhook, SMPP or email, so the number type is a business decision and the delivery mechanism is an engineering one. The inbound SMS overview covers the global mechanics; this page covers what is different about the UK.

A UK virtual or dedicated long number is a reply-capable number that presents to the recipient as a normal UK mobile number. It can be provisioned for inbound and two-way messaging, which makes it the default choice for customer support, appointment replies and any workflow where the recipient will text back rather than just receive. WorldText offers UK long numbers and international long numbers in this category, detailed on the virtual numbers service page.

The practical advantage is recognisability: a UK number is part of the national numbering range, so customers have no reason to hesitate. The practical limit is that a long number is an identifier rather than a brand, so the sender field will not carry your name. If brand recognition matters more than reply capability, pair a long number with an outbound alphanumeric sender ID and route replies against the conversation. Our two-way SMS page covers that split in detail, and the UK SMS API page covers the message flow.

UK short codes are a different category with different rules. They are Ofcom-allocated, which means the space itself is regulated rather than simply rented, and they are commonly five or six digits in the 7000 series. Several ranges remain in use alongside them, including the familiar 80xxx, 84xxx, 86xxx and 87xxx family; several ranges are in use, so check with us before assuming a particular range is available for your campaign. The short codes service page covers the operational detail.

Short codes earn their cost in specific situations: high-volume campaigns where a short number is easier to remember and harder to mistype, opt-in flows where the code itself carries the brand, and any traffic where the recipient will type the number rather than tap a link. They are a more formal commitment than a long number, which is why most UK businesses only use them for dedicated campaigns rather than everyday support.

SIM hosting covers the case where the number already exists. A business can receive text messages sent to an ordinary SIM or mobile number, with incoming messages forwarded to the business over API, webhook or email rather than sitting in a phone. The SIMs stay registered to you or under our hosting, so the number and its identity are not transferred away in a way that would break anything attached to it.

It is worth being honest about scope: SIM hosting is focused on receiving, not on bulk outbound termination. If the primary need is sending at volume, a number of the virtual numbers kind is the better tool; if the need is that customers can reach an existing UK number, SIM hosting is the honest answer. Delivery of received messages is handled exactly like other inbound routes. The SIM hosting service page explains the setup, and SMS-to-email is available as a free, low-friction variant that needs no integration at all.

Whichever number type you choose, the receiving workflow is the same: an inbound message arrives at WorldText and is delivered to your systems rather than to a person. The supported routes are HTTP webhook, SMPP and email, chosen in the portal and configurable per number. For automated handling, the auto-responder can reply on your behalf without your code being involved, which is the fastest way to stand up an opt-in or confirmation flow.

The engineering notes are the same as outbound: handle duplicate delivery by message ID, process replies idempotently, and treat the inbound message as data rather than a notification. Message states are documented on the message state and error reference, which applies to inbound tracking as well as outbound.

Testing inbound is easy: send a message to your own number from a phone and watch it appear in your webhook. Do it before launch and do it again after any portal change, because the route is configurable and configuration is exactly the sort of thing that silently drifts.