What counts as a startup here
SoCal.Startups is built and maintained by one person, and it's still under construction. Here's the honest version of how a company ends up in this directory, and what its listing does and doesn't tell you. For the technical breakdown by source and how often data refreshes, see the Methodology page.
The age rule
Of the usual startup criteria — age, headcount, funding stage, revenue, "does it feel like a startup" — age is the only one we can actually verify from the data sources below for most listings. So that's the rule we enforce: a company has to be foundable as roughly 10 years old or younger. Anything we can confirm is older than that gets left out, even if it still feels startup-ish. Headcount and funding stage aren't shown for a lot of listings simply because the source data doesn't include them — we don't guess.
Where the data comes from
- SEC Form D filings — public record of private funding rounds, filtered to Southern California and to roughly the last 3 years. This is most of the directory.
- Y Combinator — companies from YC batches located in Southern California.
- Startup news coverage — funding announcements pulled from outlets that cover the region.
- Founder self-submissions — submitted directly, reviewed by hand before anything's added.
What we deliberately leave out
SEC Form D filings aren't exclusively startups — banks, insurance companies, real estate investment vehicles, private equity holding structures, law firms, and other professional practices file Form D too, for reasons that have nothing to do with being a startup. We filter those out by hand on an ongoing basis. If one slips through, that's a miss on our end, not an intentional call — feel free to flag it.
What this isn't
This isn't a complete census of Southern California startups, and it never fully will be — bootstrapped and non-VC-backed companies don't leave the kind of public paper trail that funded companies do, so they're underrepresented here unless a founder submits directly. Treat this as a growing, imperfect snapshot, not an authoritative count.