IdeaProof - a free database of 1,091 documented company failures

Every founder hears "there are no competitors" and takes it as a green light. Usually it means the competitors already died and nobody wrote it down. Someone wrote it down.

- 339 verified case studies and 50 full post-mortems, each carrying entity type, failure reason, estimated capital lost and an evidence level
- causes normalised into a two-level taxonomy: demand, unit economics, funding, competition, execution, external shocks, governance
- $515B in quantified net losses across 862 events, free and no signup

Strongest as a pre-build check on your own market, with one honest limit the authors state themselves: the corpus skews to loud US venture-backed failures, so absence from it proves nothing.

https://ideaproof.io/startup-failure-database/

📎 Read also:
→ Startups.RIP - 5,700+ dead YC companies with post-mortems
→ LaunchVic - most pre-accelerator graduates never launch
→ Yahoo: not bad execution, the problem evaporated