How to validate a business idea in 14 days

What you'll have at the end

A 14-day record of what real people said and did when you put your idea in front of them: notes from at least ten problem interviews, a working landing page that made a specific offer, some real traffic to it, and at least one attempt to get someone to commit money or time before you'd built anything. Most importantly, a decision backed by what happened, not how you feel about the idea: keep going, change the offer, or stop and pick something else.

Before you start

• One specific problem, for one specific type of person, in a single sentence. "Freelance designers lose track of overdue invoices" is workable. "Helping small businesses with admin" is not.
• A way to reach 15 to 20 people who might have that problem: a community, past clients, a local group, LinkedIn connections.
• A free or near-free way to build a one-page site (Carrd or similar) and a free form tool to collect emails (Tally or your builder's own form).
• A small amount of money you're comfortable risking on a smoke test, even if that's £0 and you rely on organic outreach.
• A blank calendar for two weeks. This only works as a sprint, not something you dip into occasionally.

Step 1: Write the idea as a testable claim (Day 1)

Before you talk to anyone, write your idea as a claim you could be proven wrong about: "[This type of person] has [this problem] often enough that they'd pay for a way to solve it." Not "I think a scheduling tool for hairdressers could work", but "Independent hairdressers who book their own appointments lose income to no-shows at least once a week." A vague idea can't fail a test; a specific claim can.

Pick the narrowest audience you can defend, not the broadest one you hope for. You can widen later; "everyone who might like this" only makes later steps harder to read.