Are we building the right product?
Validate product decisions before hiring, scaling, or committing long-term cost.
ProductBooks may tell you to stop.
No sign-up required. Results are immediate.
Most product failures share the same root causes.
- Building features without a validated problem
- Confusing usage with real value
- Scaling before economics are proven
Start with the earliest stage you have evidence for
Each evaluator provides evidence-based scores, clear verdicts, and concrete next actions.
Problem–Solution Fit
Evaluates whether a real, painful problem exists and whether the proposed solution is meaningfully desired.
When to use: Before committing to a solution or roadmap.
Product–Market Fit
Evaluates evidence of repeatable demand, retention, and willingness to pay for the product.
When to use: When users exist, but adoption and retention are unclear.
Business Model Fit
Assesses whether the business model can sustainably support the product and market it serves.
When to use: Before hiring, scaling spend, or fundraising.
Fit Report Generator
Generates a single, investor-grade ProductBooks Fit Report by synthesising all ProductBooks stage outputs.
When to use: When you need a single, investor-grade summary.
These tools are free and standalone. ProductBooks brings them together into a single system for continuous product decision-making.
Join the ProductBooks waitlistProduct Fit Cascade
ProductBooks enforces the order teams must validate to avoid false confidence.
- Problem–Solution Fit — Are we solving a real, painful problem?
- Product–Market Fit — Do users adopt and return without pressure?
- Business Model Fit — Does the product support a viable economic model?
What ProductBooks Produces
- Clear stop / continue signals
- Evidence before scale or spend
- Alignment across product, market, and economics
ProductBooks defines what must be true before GrowthBooks scales, PeopleBooks executes, and ProfitBooks optimises.
This is for founders who
- Are making product decisions under uncertainty
- Want evidence before scale
- Prefer clarity over speed
This is not for
- Feature-driven roadmap builders
- Teams seeking tactics without validation
- Companies avoiding economic truth
ProductBooks exists for founders who understand that what you choose not to build matters as much as what you do. This is a long-term system for serious decision-making.
Run a free evaluator