58K GitHub stars
$ gstack office-hours

gstack, now on the web

YC CEO's product planning tool. No CLI, no setup. Just your idea.

gstack-session
gstack > _

Free. No signup required. Public only.

The real gstack

Garry Tan's product planning tool. 58K stars on GitHub. Now in your browser.

Free grade, Pro deep-dive

Get a free grade card instantly. Go Pro for market research, alternatives, and full design docs.

Share your grade

Get your A-F grade card. Share it on Twitter/Threads. Flex or learn.

Your idea might suck. Let's find out.

6 forcing questions. No hand-holding. No "great idea!" BS. Just the truth about whether your startup has legs.

01

Drop your idea

Type your startup idea. One sentence or a novel -- we don't care.

02

Get grilled

6 questions that expose whether there's real demand, real users, real timing.

03

Get your grade

A-F. No sugarcoating. Share it, or upgrade for the full deep-dive.

Recent Evaluations

A
2m ago

AI Code Review SaaS

"Clear demand, narrow wedge, perfect timing."

C
2m ago

Social Media for Pets

"Cute but no desperate user. Who pays?"

F
2m ago

Blockchain for Restaurants

"Solution in search of a problem."

Simple pricing

Free to try. $19/mo to go deep.

Free

$0/forever

Quick Eval. 1 per month. Public only.

  • 6 forcing questions
  • A-F grade card
  • Shareable public URL
  • OG card for social
  • Push back / follow-up
  • Market research
  • Design document
  • Private sessions
RECOMMENDED

Pro

$19/month

Full Office Hours. 10 sessions/month.

  • Everything in Free
  • Unlimited push back (20 turns)
  • Market research (web search)
  • Premise challenge
  • Alternative generation
  • Full design document
  • Public or Private
  • Session history
  • PDF/Markdown export

Ready to find out if your idea has legs?

Takes 5 minutes. No signup. No credit card.