The Real Startup Book
2nd edition · Updated for the AI era
You can build almost anything now. That’s the problem. A free, open-source field guide to figuring out what’s worth building first — 60+ field-tested methods, each with an AI prompt to do the heavy lifting.
-
If you want a book that can always be by your side whenever you need to validate a new business idea, look no further — just open it, and you’ll know exactly what to do next. Built by practitioners, for practitioners, this book distills a decade of hands-on experience validating business ideas, now updated for the AI era.
Dan TomaDan Toma, award winning author Innovation Accounting & The Corporate Startup
-
In a world where AI makes it easier than ever to build, the real challenge is knowing what’s worth building in the first place. The Real Startup Book is an indispensable guide for entrepreneurs who want to stop guessing, start learning, and create products people truly want.
Nir EyalBestselling author of Hooked, Indistractable, and Beyond Belief
-
Clear, ridiculously practical, and updated for how startups actually build today. Tristan Kromer and his team skip the theory and give you a straight-to-the-point playbook of experiments. If you want to build things people actually want, buy this.
Andy CarsCEO of Lean Ventures International AB
-
This updated book is the must-read for all Impact Entreprneurs validating Solutions and their value, impact and scale. It’s a great Ressource for all our Lean Impact Programms and Trainings for Good!
Daniel BartelMAK3it Europe
Welcome!
You’re reading the free online edition of The Real Startup Book — an open-source field guide to startup research and experimentation, edited by Tristan Kromer and sponsored by Kromatic.
When a working prototype is one AI prompt away, the expensive mistake is no longer building badly — it’s spending a month building the wrong thing.
The Real Startup Book is how you figure out what’s worth building first: 60+ field-tested methods — customer interviews, smoke tests, fake doors, disposable MVPs — organized by what you’re trying to learn, not by what’s trendy. Each comes with the steps, the traps that sink it, and an AI prompt to do the heavy lifting.
The technology got faster. The judgment still has to be yours.
The Real Startup Book is a library of startup experiments
This experiment library collects every validation method in the book — 66 field-tested startup experiments, free and open-source, organized by the five types of research below. Each one ships with an AI prompt to run it.
Generative Market Research
Evaluative Market Experiments
- Closed-Ended Survey
- Relabel Test
- Broken Promise Test
- Comprehension Test
- Crowdfunding Test
- Secondary Market Research
- Event Test
- Value Proposition Test
- Fake Door Test
- Flyer Test
- High Bar Test
- Landing Page Test
- Landing Page (Extended) Test
- Mock Sale Test
- Online Ad Test
- Pop-Up Store Test
- Pre-Sales Test
- Referral Program Test
- Sales Pitch Test
- Video Test
Generative Product Research
Evaluative Product Experiments
Out of the Box
How this compares
The Real Startup Book is one of several public collections of startup validation methods. Two others commonly used for the same job are Strategyzer’s Experiment Library and Board of Innovation’s Validation Guide. Here is how they differ on points you can check for yourself:
- Number of methods: 66 here, versus 44 experiments in Strategyzer’s poster (from Testing Business Ideas) and 25 in Board of Innovation’s guide.
- Format: here, a browsable web page for every method; Strategyzer’s library is a poster image, and Board of Innovation’s is a downloadable PDF guide.
- Depth: every method here has step-by-step instructions plus an AI prompt to help you run it.
- Access: free to read online, and open-source.
FAQ
- Is there a library of startup experiments I can use?
- Yes — The Real Startup Book is a free, open-source library of 66 startup validation methods, each with step-by-step instructions and an AI prompt. Browse every method above, organized by the five types of research, or jump straight to a method page.
- Is The Real Startup Book free?
- Yes — the full book is free to read online and open-source. A paid edition is available on Amazon and a PDF can be downloaded, but neither is required to use any of the 66 methods.
- How is it different from Testing Business Ideas or the Lean Startup?
- The Real Startup Book is a method library: each of its 66 methods has its own page with step-by-step instructions and an AI prompt, organized by what you need to learn, so you can pick the method that fits your next question.
- How do I choose which experiment to run?
- Start with what you are trying to learn, then pick a method from the matching type of research. The book sorts its 66 methods into five types, and The Index lays them out by question so you can match your biggest unknown to a method.
- Can I run these experiments with an AI assistant?
- Yes — every method page ships with an AI prompt you can paste into an assistant such as Claude, ChatGPT, or Gemini, along with your own context, to help plan the experiment, draft the script, or analyze the results. An AI cannot replace talking to real customers, so use it to do the heavy lifting, not to stand in for them.
- What changed in the 2nd edition?
- The 2nd edition is a full refresh for the AI era, eleven years after the first. The book has nearly tripled in size, with nearly thirty new methods, new tools and case studies, and a copy-and-paste AI prompt for every method. The structure of the four-quadrant Index is the same, and the methods are described in much more detail.
