Andrew Crossley

    Idea to MVP questions, answered

    The questions founders ask between having an idea and having something real in front of paying users — scope, cost, timeline and validation. Answers reflect the Crossley Method: discover, validate, prototype, build, launch, first revenue.

    How do you build an MVP?

    Build an MVP by picking one job a specific user will pay to have done, designing the single shortest flow that completes it, and shipping only that. Validate demand before building — interviews plus a paid or committed signal. Build in four to six weeks with off-the-shelf infrastructure, launch to a narrow group, and measure whether they complete the job and come back.

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    How much money do I need to build an MVP?

    A focused software MVP costs roughly £5,000–£15,000 built with AI-assisted tooling and a small scope, £20,000–£50,000 with a freelance or agency team, and £60,000–£120,000 for a complex or regulated product. The main cost driver is scope, not day rate: every extra flow adds design, build, testing and support cost. Budget 20% for post-launch iteration — that is where the learning is.

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    How do you build an AI MVP?

    Build an AI MVP by choosing one task where being right 80% of the time is still useful, wrapping a hosted model rather than training your own, and designing the interface around correction — users must be able to see, edit and accept output. Set an evaluation set before launch, measure task success and human-override rate, and only consider fine-tuning once the workflow itself is proven.

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    How long does it take to launch a product?

    A focused MVP goes from idea to launched product in six to twelve weeks: one to two weeks of discovery and validation, four to six weeks of build, one to two weeks of pilot and fixes. Complex, integrated or regulated products take four to nine months. Delays almost always come from scope changes and slow decisions, not from engineering speed.

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    THE FRAMEWORK

    The Crossley Method: idea to first revenue in seven stages

    See the full method
    1. STAGE 1DiscoverWeek 1
    2. STAGE 2ValidateWeek 2
    3. STAGE 3PrototypeWeek 3
    4. STAGE 4Build MVPWeeks 3-4
    5. STAGE 5LaunchWeek 5
    6. STAGE 6First RevenueWeek 6
    7. STAGE 7ScaleOngoing