Accel is one of the world’s leading venture firms, founded in 1983 by Arthur Patterson and Jim Swartz and headquartered in Palo Alto. Its “prepared mind” philosophy has backed category-defining companies including Facebook, Slack, Dropbox, Atlassian, CrowdStrike, UiPath, Spotify, Vercel, Anthropic, and Perplexity. But a portfolio list is a marketing document. What we track on APIs.io is something more concrete: which of those companies actually ship a developer surface, and how good it is.
The portfolio’s API footprint
Accel has 766 portfolio companies tracked on the network, of which 178 — 23% — publish APIs indexed here. That ratio is the interesting part. Nearly four in five portfolio companies leave no measurable developer surface at all. The API is the exception, not the rule, even inside a fund this deep in enterprise software and developer tools.
Of the 178 that do publish, the network sorts them into rating bands:
- Exemplar (8): the fully documented, agent-ready surfaces — including Anthropic, Sentry, UiPath, Airbyte, Vercel, and 1Password
- Strong (21): solid coverage with minor gaps — Slack, Atlassian, Webflow, DocuSign, Merge, Discord, and more
- Developing (47): usable, with real gaps to close
- Thin (60): limited public surface area
- Emerging (34) and Minimal (8): early, largely undocumented, or almost no developer surface at all
The distribution is top-light and bottom-heavy. Only 29 of Accel’s 178 API-publishing companies clear the Strong-or-better line. The largest single band is Thin, at 60. Being well-funded and being well-documented are, it turns out, only loosely correlated.
One observation
The strongest names in Accel’s book are the ones whose product is the API. Anthropic, Sentry, UiPath, Airbyte, and Vercel sit at the top because a developer surface is not a side channel for them — it is the thing customers buy. The thin and emerging tail is dominated by companies where the API is an integration afterthought bolted onto a UI-first product. That is the signal a portfolio graph surfaces that a logo grid never will: the difference between companies that treat their API as the product and companies that treat it as plumbing.
Takeaway
Accel’s footprint on the network is a reminder that venture backing and API maturity are separate axes. 178 API providers across seven rating bands, with the mass sitting in Thin and Developing, is what a real portfolio looks like when you measure it instead of listing it. Walk the full band-by-band breakdown, from Krux at the top to the minimal tail, on Accel’s page.