Real-time inference infrastructure for generative video and world models
Reactor (reactor.inc) is a San Francisco developer platform for real-time generative video and world-model inference, founded in 2025 by Alberto Taiuti and Bryce Schmidtchen. On October 5, 2026 it announced that NVIDIA (NVentures) and Sapphire Ventures joined its Series A led by Lightspeed Venture Partners, bringing total funding to $74 million (up from $59 million at its May 2026 stealth launch); the release did not break out the incremental primary amount from the new investors.
Enterprise Software📍 San Francisco, CaliforniaFounded 2025
Current Valuation
Private
PRIVATE
IPO Outlookprivate
Is Reactor going public?
No. Reactor is private and has not filed to go public. There is no S-1 on file.
What is Reactor's valuation in 2026?
No confirmed valuation is on record for Reactor. The roster shows funding and investors where they are public; it does not estimate a mark.
Has Reactor filed an S-1?
No public S-1 is on file for Reactor.
Who are Reactor's investors?
Reactor's investors include Lightspeed Venture Partners, NVIDIA (NVentures), Sapphire Ventures, WndrCo, Amplify Partners, Sky9 Capital and 1 more.
How much has Reactor raised?
Reactor has raised $74M in total across 1 disclosed round, most recently a Series A (expanded) in Oct 2026.
Is Reactor publicly traded — can you buy Reactor stock?
No. Reactor is a private company — its shares are not listed on any exchange and there is no ticker. The routes to exposure are pre-IPO secondary marketplaces and funds (accredited investors), employee tender offers when the company runs one, and public companies with read-through exposure. QuantLogix maps every route it can verify for Reactor on its Pre-IPO Access Desk.
Answers are derived from the roster record shown on this page — filing status, last round and confirmed marks. Where the record is silent, the answer says so rather than guessing.
Company Profile
CEO
Alberto Taiuti
Founded
2025
HQ
San Francisco, California
Total Raised
$74M
Growth
Total funding $74M after NVIDIA and Sapphire join Series A (Oct 2026)
IPO Status
private
Fundraising Status
Series A (expanded) · this month
privateTotal raised $74M1 disclosed rounds
Funding History
Round
Amount
Date
Lead Investor
Post-Money
Series A (expanded)
—
Oct 2026
Lightspeed Venture Partners
—
Vertical Intelligence — AI / ML
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Talent Signal
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Private-company numbers are not real-time. Reflects publicly disclosed valuations from press releases, news reports, and tender offers as of recent date. Refreshed quarterly.