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Learn how YC founders got their first customers · Playbook

Learn How YC Founders Got Their First 1000 Customers (By Channel)

Cold email, Reddit, the YC network, one viral tweet — across 300+ YC companies, the channel that worked is shockingly concentrated.

May 10, 2026 · 9 min · distribution · growth · cold outreach

There is no 'general' growth playbook. The channel that gets a B2B SaaS to 1,000 customers will bankrupt a consumer app, and vice versa. The First 1000 Customers Database tags every YC company by the channel that actually worked for them. The distribution is narrower than founders expect.

The channel mix

First-1000-customer channel by company type
Company typeChannel that workedShare
B2B SaaS (engineering tools)Founder cold email + HN launch~52%
B2B SaaS (ops/HR/finance)Founder-led outbound (LinkedIn + email)~46%
Consumer socialOne viral post (Twitter / TikTok / Reddit)~61%
Consumer marketplaceManual supply seeding in one city~58%
FintechPartnership with existing distribution~44%
Devtools / APIGitHub launch + docs SEO~49%
Source note: From the YC First 1000 Customers Database. Multi-channel companies are tagged by primary driver.

The cold-email pattern that actually worked

  • Sent by a founder, not a BDR (every B2B SaaS survivor in the sample).
  • Subject line was 4–7 words, lowercase, no emoji.
  • Body referenced a specific recent action by the recipient (raised a round, hired a role, shipped a feature).
  • Asked for a 15-minute call, not 30. The smaller ask converted ~3x better.

The viral-post pattern (consumer)

Across the consumer companies in the database, the 'viral moment' was almost never an accident. It was the third or fourth deliberate attempt at a launch post — same hook, refined three times. Founders who treated launch as a single event consistently underperformed founders who treated it as a campaign of 4–6 posts over two weeks.

Key takeaways

  • B2B = founder cold email; consumer = a campaign of launch posts.
  • Marketplace founders manually seed supply in one city before any code.
  • Cold emails ask for 15 min, not 30. Sent by a founder, not BDR.
  • Viral 'moments' are usually the 3rd–4th deliberate attempt.

Sources

Databases that go deeper on this topic

Most readers of this post bundle these together — each one drills into a different angle of the same story.