The short answer
Most contracts in the UK can be made in any form: face to face, on the phone, by email or in a WhatsApp chat. There is no general rule that a contract has to be written down or signed. If you and your client clearly agreed the work and the price, and you both meant it, you may well have a contract.
What makes an agreement binding
Broadly, the courts look for:
- An offer and an acceptance. "I can do it for £1,200, starting Monday" followed by "Great, go ahead" is the classic shape.
- Terms clear enough to enforce. What is being done, for how much, and roughly when.
- An intention to be bound. Business dealings are presumed to be serious. Friendly chat, or "subject to contract", may not be.
- Something given in return (in England and Wales and Northern Ireland). Usually that's just payment for the work. Scots law doesn't need this.
Where messages fall short
Messages are good at recording that you agreed. They are often poor at recording what you agreed:
- The deal is spread across dozens of messages, voice notes and calls.
- Important things are never said at all: what happens if the client cancels, when payment is due, who owns the work, how many changes are included.
- Later messages change earlier ones, and it isn't clear which version won.
- Chats get deleted, phones get lost, and screenshots can be cropped.
If there's a dispute, the argument is rarely "was there a contract?" and usually "what did it say?"
Some agreements need more than a chat
A few kinds of agreement have formal rules about writing or signing, and a casual message may not meet them. Examples include contracts to sell or buy land or property, personal guarantees, and some consumer credit agreements. Tenancies have their own rules about the written information a landlord must give. Each part of the UK sets its own rules.
If you deal with private customers, consumer law also gives them rights, such as a 14-day right to cancel many contracts made away from your premises or online. You have to tell them about it, whatever form the agreement takes.
How to turn a chat into something you can rely on
- Write down the deal in one placeThe work, the price, the dates, payment terms, and what happens if either of you pulls out.
- Send it for the client to readSo nothing rests on what someone thinks they said.
- Get it signedA signature shows they read that version and agreed to it.
- Keep a recordWho signed, when, and proof the document hasn't changed since.
AgreeVia does those steps on your phone. Start from a template or turn the chat messages where you agreed the job into a draft. Your client signs from a link without an account, and every view and signature goes into a tamper-evident record anyone can check at agreevia.co.uk/verify.
This guide explains the general position in the UK as we understand it on 10 October 2026. The law differs between England and Wales, Scotland and Northern Ireland, and it changes. If something important turns on it, talk to a solicitor.
Get to work
Agreed the job in messages? Put the price, dates and scope into a template, and send it to your client to sign.
Free for 3 documents a month, no card needed. AgreeVia works in your browser today, and iPhone and Android apps are coming soon.