Findings · 1,828 YC startups · W24 – F26

48% of recent YC startups host on Vercel.

The same scanner, run over every company from W24 to F26. Single scans miss things; this many don't.

Vercel 48%

Behind Cloudflare 22%Framer 9%Everything else 21%

1,828

startups scanned, W24 – F26

median vendors visible per company

90%

run email on Google Workspace

11%

verified a domain with an AI vendor

01 · Where the homepage is hostedOpen & share ↗

Vercel hosts 48% of homepages, more than the next four combined.

Label	Share	Value
Vercel		48%
Behind Cloudflare		22%
Framer		8.8%
AWS		8.6%
Google Cloud		2.0%
GitHub Pages		1.9%
Netlify		1.9%
Render		1.3%
Fastly		0.9%
Other		3.7%
Unknown		1.1%

One answer per company: the platform seen in response headers, CNAME or site generator; otherwise the IP owner. "Behind Cloudflare" means Cloudflare proxies the site and hides the origin. Cloudflare sits in front of 32% of all homepages, whatever the host.

02 · How it shifts, batch by batchOpen & share ↗

Vercel hosts 52% of 2026 batches, up from 41% in 2024. Framer went the other way: 15% → 5%.

100%

W24S25F26

● Hosted on Vercel 40%→48%● Next.js 38%→54%● Built with Framer 17%→4.3%● Google Workspace 89%→90%● Cloudflare DNS 36%→47%● Verified an AI tool 17%→13%

Share of companies in each batch. Batches with fewer than 30 scanned companies are left out. Older batches have had longer to rebuild their sites, so this mixes "what new companies pick" with "what companies move to".

03 · Google Workspace vs Microsoft 365Open & share ↗

90% run email on Google Workspace, 18.5× Microsoft 365. Yet 20% have a Microsoft 365 tenant verified in DNS, mostly for things other than mail.

Label	Share	Value
Google Workspace		90%
Microsoft 365		4.9%
Cloudflare Email Routing		0.6%
Namecheap Email Forwarding		0.4%
Other		1.2%
None detected		2.6%

From MX records (SPF when MX points at a filtering gateway). Forwarders like Cloudflare Email Routing are counted as what the domain runs.

04 · What the homepage is built withOpen & share ↗

Next.js powers 46% of homepages. Site builders (Framer, Webflow and friends) make up 18%, ahead of Framer at 10%.

Label	Share	Value
Next.js		46%
Framer		9.9%
Webflow		6.4%
Astro		5.0%
SvelteKit		1.0%
WordPress		0.8%
Express		0.5%
Squarespace		0.4%
Nuxt.js		0.3%
Other		1.8%
None detected		28%

Site builders win over the frameworks they're made with (a Framer site is "Framer", not React). "None detected" is mostly plain or client-rendered HTML with no fingerprint.

05 · Who runs their DNSOpen & share ↗

Cloudflare DNS runs DNS for 41%, 3× GoDaddy DNS. 25% still use the DNS that came with their registrar.

Label	Share	Value
Cloudflare DNS		41%
GoDaddy DNS		14%
Amazon Route 53		11%
Namecheap DNS		11%
Vercel DNS		7.4%
Google Cloud DNS		4.8%
NS1		2.0%
Azure DNS		0.3%
Other		0.3%
Unrecognised		7.7%

From NS records.

06 · AI tools with a verified domainOpen & share ↗

11.4% have verified their domain with an AI vendor. Anthropic leads at 8.3%, 1.9× OpenAI.

Label	Share	Value
Any of these		11%
Anthropic		8.3%
OpenAI		4.3%
Cursor		1.8%
Mistral AI		0.1%
ElevenLabs		0.1%

From TXT verification records, which companies add to set up SSO or a team workspace. Individual seats on a credit card leave no trace, so this undercounts usage.

07 · Workspace SaaS visible in DNSOpen & share ↗

Anthropic (8.3%) and OpenAI (4.3%) are the most-verified tools. Most tools need no DNS record at all, so these are lower bounds.

Label	Share	Value
Anthropic		8.3%
OpenAI		4.3%
Slack		3.5%
Notion		2.6%
Cursor		1.8%
Zoom		1.7%
1Password		1.4%
Tailscale		1.2%
Cloudflare dashboard SSO		1.0%
Atlassian		1.0%

A company can appear in several bars.

08 · Who sends email for themOpen & share ↗

19% authorise a sending service in SPF; Amazon SES is the most common at 7.5%.

Label	Share	Value
Amazon SES		7.5%
HubSpot		3.9%
SendGrid		2.0%
Resend		1.7%
Firebase Auth email		1.4%
Brevo		1.4%
Mailgun		1.0%
MailerLite		0.7%
lemlist		0.7%
Klaviyo		0.5%

From SPF includes and verification records. Services that send from a subdomain (common for Resend and Postmark) aren't visible from the apex domain.

09 · Vendors visible per companyOpen & share ↗

The median company shows 6 vendors from public signals alone (middle half: 5–8); the most shows 27.

15%

75%

8.8%

0.9%

0.3%

1–45–910–1415–1920+

Medium and high confidence detections only.

10 · The most common full stackOpen & share ↗

The single most common combination (Vercel + Cloudflare DNS + Google Workspace + Next.js) covers 13% of companies.

Vercel + Cloudflare DNS + Google Workspace + Next.js13%

Behind Cloudflare + Cloudflare DNS + Google Workspace + None detected5.7%

Vercel + Vercel DNS + Google Workspace + Next.js5.1%

Vercel + GoDaddy DNS + Google Workspace + Next.js4.7%

Vercel + Namecheap DNS + Google Workspace + Next.js3.7%

Behind Cloudflare + Cloudflare DNS + Google Workspace + Next.js3.5%

Out of 1,828 companies.

List source

YC's public directory via yc-oss/api, W24 – F26, inactive companies excluded. 1,873 listed, 1,828 scanned.

Scan method

One homepage fetch plus apex DNS, 8 at a time, as UnderhoodBot. Same code as every single scan. Scanned 2026-09-28.

Failures

45 skipped: 33 timeout, 7 domain does not resolve, 4 TLS error, 1 too many redirects.

What counts

Medium confidence and up; low hints are excluded. Anything behind a login, on subdomains or loaded later by a tag manager is invisible, so every number is a lower bound. Opted-out domains are left out.