Sign up through Startup School
- Who acts
- Founder
- The clock
- Approval may take up to a week
Founder matching · How it works guide
How Y Combinator Co-Founder Matching Works
A match forms only when both founders accept an invitation. Expect up to a week of approval, then up to 15 invitations a week, and 2 to 4 weeks of close work before you judge whether the match fits. Nothing moves until both people act. [1] [2]
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A match, step by step: who acts, and what happens if nobody does
Build your profile
- Who acts
- Founder
- The clock
- No clock stated
- If nobody acts
- Thinner profile for others to judge [1]
See fitting profiles and filter
- Who acts
- Founder
- The clock
- No clock stated
- If nobody acts
- Nothing is sent [1]
Send an invitation
- Who acts
- Founder
- The clock
- Up to 15 a week
- If nobody acts
- Your weekly allowance goes unused [2]
Invited founder accepts
- Who acts
- Other founder
- The clock
- No clock stated
- If nobody acts
- No match forms [1]
Arrange a call
- Who acts
- Both
- The clock
- No clock stated
- If nobody acts
- Nothing further happens [1]
Close work to judge fit
- Who acts
- Both
- The clock
- 2 to 4 weeks recommended
- If nobody acts
- Fit stays unjudged [2]
| Step | Who acts | The clock | If nobody acts |
|---|---|---|---|
| Sign up through Startup School | Founder | Approval may take up to a week | Profile can’t be used until approved[2] [1] |
| Build your profile | Founder | No clock stated | Thinner profile for others to judge[1] |
| See fitting profiles and filter | Founder | No clock stated | Nothing is sent[1] |
| Send an invitation | Founder | Up to 15 a week | Your weekly allowance goes unused[2] |
| Invited founder accepts | Other founder | No clock stated | No match forms[1] |
| Arrange a call | Both | No clock stated | Nothing further happens[1] |
| Close work to judge fit | Both | 2 to 4 weeks recommended | Fit stays unjudged[2] |
A match exists only when both founders say yes
Sending an invitation doesn’t create a match. The match forms only when the other person accepts, and only then do you arrange a call. Some invitations will go unanswered, because nothing forms without a yes. That is the core rule, and it sets how you should plan your 15 weekly invitations. [1]
For the founder who sends invitations
Sign-up starts through Startup School, and the profile is created afterwards. Approval may take up to a week, and until then you can’t use the service. Once approved, you see fitting profiles, filter them, and invite up to 15 people a week. The Startup School course is optional, at about 7 weeks and 1 to 2 hours a week. [2] [1] [3]
After a match, plan for 2 to 4 weeks of close work before you decide. That is YC’s recommendation for judging fit, and it is the longest step in the process. [2]
For the founder who gets an invitation
An invitation is a choice, not an obligation. Accepting forms a match, and then the two of you arrange a call. Your profile has to be approved before you can use the service, so an invitation can only reach you after approval. [1] [2]
Where people get stuck
The approval wait is the first trap, and it is easy to plan around. The second is a match that goes quiet. One March 2026 review describes a match that “just disappeared” after conversation. The third is profile visibility, which the matching page and privacy policy describe differently. See the complaints page for what helps. [4] [1] [5]
Bibliography
Sources
- YC Co-Founder Matching homepage (official)
- Startup School FAQ (co-founder matching) (official)
- Startup School homepage (official)
- Trustpilot: Y Combinator reviews (platform-hosted)
- Y Combinator privacy policy and Terms of Use (official)