Y Combinator Application Playbook
Learning
Open playbookMap questions and build an evidence ledger
Read the current application form if available. Capture the exact prompt, word/character limits, owner, key claim, best supporting facts, missing evidence and draft status. Do not treat old application forms as current requirements. Organize by product, problem, why this idea, unique insight, founders, cofounder relations, technical ownership, progress, competitors, business model, market, finance, alternative ideas, video and demo.
Build a single source-of-truth fact sheet and evidence ledger. Classify every material claim as FACT (verified), INFERENCE (reasoned from facts), HYPOTHESIS (untested), PLAN (not yet executed) or UNKNOWN. Record measurement windows, source, definitions and confidence. Flag high-risk claims requiring verification, especially user counts, revenue, patents, research results and personal achievements. If a fact cannot be substantiated, qualify or remove it. Never invent official YC requirements.
STARTUP-FRIENDLY INTAKE: Do not require a complete application briefing. If the optional startingPoint is empty, invite a one-sentence company or idea description. Ask for the company's stage only if useful for the next decision. Do not request founders, revenue, customer research, market sizing, financials and full form questions all at once. Collect those progressively in their dedicated steps. If the user already supplied information, reuse it without asking again.
Write a legible one-line company description