Validation
Find out if people truly want it — before you build it.
4
concepts
3
tools
24
books
How validation works — step by step
Read these in order. Each takes about 3 minutes.
- 01
Customer discovery
Go and talk to real potential customers to check that the problem you want to solve actually exists.
First step: Pick a specific group of people (e.g. 'freelance designers in London', not 'everyone').
- 02
The Mom Test
Ask customers about their real life and past behaviour — never 'do you like my idea?'.
First step: Talk about their life, not your idea.
- 03
Lean Canvas
A one-page startup plan that starts with the problem, not the product.
First step: Problem: top 3 problems.
- 04
Fake-door & smoke tests
Test demand before building by offering something that doesn't exist yet and measuring who tries to get it.
First step: Write a clear one-line promise.
Tools for validation
Most useful at these stages
Essential reading
The Lean Startup
Eric Ries
Treat your startup like a series of experiments. Build a small version, measure how real people react, learn, and adjust fast instead of guessing for months.
The Mom Test
Rob Fitzpatrick
How to talk to customers without getting fooled by polite lies. Ask about their real past behaviour, not their opinion of your idea.
The Four Steps to the Epiphany
Steve Blank
The origin of 'customer development': discover, validate, create demand, then build the company — in that order.
Business Model Generation
Alexander Osterwalder & Yves Pigneur
Introduces the Business Model Canvas: one page with nine boxes that shows how a business makes, delivers and earns from value.
Running Lean
Ash Maurya
A step-by-step playbook for applying lean ideas, including the Lean Canvas, a one-page startup plan.
Inspired
Marty Cagan
How the best tech companies discover and build products customers love, by tackling the biggest risks early.
Explore by tag
From the library (24)
Competing Against Luck: The Story of Innovation and Customer Choice
Clayton Christensen's jobs-to-be-done theory, explaining how to understand what customers really want and create successful innovations.
Competing Against Luck: The Story of Innovation and Customer Choice
Clayton Christensen's Jobs-to-be-Done framework shows how understanding what customers hire products to do leads to breakthrough innovation. Essential for founders building products people actually want to buy.
FOCUS Framework: How to Find Product-Market Fit
A practical guide by Justin Wilcox that provides step-by-step instructions on how to find product-market fit through customer experiments. Includes 5 workbooks with 44 experiment exercises covering customer interviews, opportunity sizing, MVPs, and scaling.
Jobs to be Done: Theory to Practice
Anthony Ulwick's practical guide to Jobs-to-be-Done theory and Outcome-Driven Innovation. Learn how to understand what customers really want and create products they'll actually buy—with an 86% success rate.
Lean B2B: Build Products Businesses Want
Étienne Garbugli's essential guide to B2B customer development, packed with over 20 case studies. This book provides a proven process to get from idea to product-market fit in business-to-business markets using lean startup principles.
Lean UX
Lean UX adapts user experience design to the Lean Startup world, helping product teams and founders build, measure, and learn faster by emphasizing collaboration, experimentation, and continuous learning.
Starting a StartUp: Build Something People Want
A founder-focused book on how to identify real customer problems and build products that people truly want. Emphasizes idea validation, customer discovery, and iterating toward product–market fit—core concepts for any early-stage startup founder.
The Four Steps to the Epiphany: Successful Strategies for Products that Win
Steve Blank's pioneering book on customer development that launched the lean startup movement, providing a systematic framework for discovering and validating customer needs.
User Story Mapping: Discover the Whole Story, Build the Right Product
Jeff Patton's definitive guide to user story mapping—a technique for keeping the big picture in view while building products. Essential for product managers and founders who want to build what customers actually need.
UX for Lean Startups
UX for Lean Startups shows founders and early-stage teams how to do effective user experience research and design with limited time and resources, aligning UX work with Lean Startup experimentation.
Biodesign: The Process of Innovating Medical Technologies
Must-have book for starting a medical device company, featuring a great customer discovery process. By Zenios, Makower, Yock et al.
Continuous Discovery Habits
A hands-on guide for product leaders and startup founders on how to embed continuous discovery practices—regular customer interviews, rapid experiments, and assumption testing—into their workflow. It shows how to reduce product risk, increase learning speed, and consistently ship features that drive both customer and business value.
Deploy Empathy: A Practical Guide to Interviewing Customers
A practical guide to customer interviewing that teaches founders and product teams how to conduct effective customer research interviews. The book provides frameworks, scripts, and templates for discovering customer needs, testing hypotheses, and making better product decisions based on real customer insights.
Four Steps to the Epiphany
Steve Blank's "Four Steps to the Epiphany" is a seminal work that outlines a customer development process for startups. It highlights the importance of understanding customer needs and iterating based on feedback, offering a comprehensive approach to building successful startups.
Inspired
Marty Cagan's book offers insights into product management and development, focusing on creating products that resonate with customers. It's essential for tech startup founders.
Intercom on Product Management
Intercom's collected wisdom on building products customers love. Short, practical essays from a company that scaled to serve over 25,000 businesses.
Lean Customer Development: Building Products Your Customers Will Buy
Cindy Alvarez's practical guide to customer development for product teams. Learn how to talk to customers and validate ideas before building, based on her experience at Yammer and Microsoft.
My First 1000 Dollars
Yogi Raj's workbook provides actionable strategies for acquiring initial customers, a critical step for any startup. It's a hands-on guide for founders looking to build a customer base from scratch.