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UPDATED 2026.06.07
rl-list.com · Vendors · Sepal AI
#13

Sepal AI

Commercial
medium confidence
www.sepalai.com ↗ · Status: acquired confirmed · Founded 2024

Sepal AI is a YC-backed (S24) San Francisco data-research company that builds high-quality training data, expert-graded evaluation benchmarks, and reinforcement-learning environments for frontier LLMs, drawing on a network of 20k+ domain experts (PhDs, finance, medical, STEM). It was acquired by Mercor in February 2026.

Key facts
Headquarters
San Francisco, USAconfirmed cite
Headcount band
unknown cite
Total raised
$500Kreported cite
Last round
Pre-seed, ~$500K, 2024-09-25 (per Crunchbase aggregator; not independently confirmed by a primary announcement)reported cite
SOC 2
unknown
What they sell
mixedconfirmed cite
Open source
noestimated
Deployment
unknown

Scale & velocity

Current headcount
~13-15 core team (YC team size 15; getlatka 13 for 2024). LinkedIn public snippet shows 51-200 band (likely includes contract experts)reported cite
Headcount growth
unknown
Open roles
unknown cite
Other locations
unknown
Distributed / remote
unknown

Research depth

Has researchers
yesreported cite
Researcher count
unknown
Backgrounds
Co-founders ex-Turing (built/scaled the LLM-trainer business; Robi Lin scaled trainers 50 to 800+; Kat Hu managed 500+ AI trainers), Co-founder Robi Lin formerly at Bain & Co.; co-founder Kat Hu former McKinsey consultant, Co-founder Fedor early engineer at Vercel and Newfront, Engages 20k+ network of academic PhDs and domain professionals (STEM, medical, finance, business)reported cite
Papers / benchmarks
SheetBench-50, first public financial-analyst-grade benchmark of AI agents on real spreadsheet/financial workflows (50 tasks), built in partnership with HUD; tasks validated by finance pros from PwC, Cisco, Charles Schwab, Fannie Maeconfirmed cite

Capital

Total raised
~$500K disclosed (single pre-seed round, Sep 2024) per aggregators; YC profile separately states 'several million dollars from leading investors' (unresolved conflict)reported cite
Last round
Pre-seed, ~$500K, 2024-09-25 (per Crunchbase aggregator; not independently confirmed by a primary announcement)reported cite
Investors
Y Combinator, Metaplanet Holdings, SID Venture Partners, Sterling Road, Team Ignite Venturesreported cite
Valuation
unknown
Revenue signals
Third-party (getlatka) claims ~$2M revenue with a 13-person team in 2024, single unverified source, not vendor-confirmedreported cite

Security & compliance

SOC 2
unknown
Other certifications
unknown
Security page
unknown

Product

What they sell
mixedconfirmed cite
Open source
noestimated
License
unknown
Deployment model
unknown
Maturity
GAestimated cite
Notable customers
⚑Top AI research labs (unnamed; frontier-lab ties referenced in Mercor acquisition rationale) self-claimed Multiple Fortune 500 companies (unnamed) self-claimed HUD (co-builder/collaboration partner on SheetBench-50, NOT a customer) verified cite

Buyer analysis

Best fit: Buyers needing expert-validated evaluation environments and RL/training data for complex domains (notably finance/spreadsheet analyst workflows and advanced science), note the team is now part of Mercor following the Feb 2026 acquisition.

How we verified this

Independently re-verified the highest-risk claims. CONFIRMED: Mercor's Feb 2026 acquisition (Orrick + Mercor/founder LinkedIn posts), founding year 2024 and SF HQ (YC), and SheetBench-50 benchmark co-built with HUD (HUD case study + HuggingFace). Funding remains at 'reported', multiple aggregators report a single ~$500K pre-seed round, but this conflicts with the YC profile's 'several million dollars' claim and no primary press release exists; not upgraded. Investors are consistent across aggregators but lack a primary announcement (kept 'reported'). KEY CORRECTIONS: (1) headcount_band downgraded from '11-50' to 'unknown', LinkedIn shows a 51-200 band while YC lists 15, an unresolvable conflict; a startup of this stage is not genuinely 200+, and neither band is cleanly supportable. (2) HUD reclassified from a 'customer' to a co-builder/collaboration partner, it is a benchmark co-author, not a paying customer; the Fortune 500 and AI-lab customers remain correctly self-claimed (unnamed). soc2/certifications/security all correctly remain unknown (no trust page found). This is the correct company matching the 'expert evaluation environments' directory note.

Related vendors

Mechanize CommercialAfterQuery CommercialDeeptune CommercialBespoke Labs Commercial

Sources

  1. www.sepalai.com/ · 2026-06-07, Official site (returned 402 on fetch; confirmed via search snippets) - tagline 'Making models smarter and safer', data research company
  2. www.sepalai.com/careers · 2026-06-07, Careers page; open roles incl. Applied Research Engineer, Senior/Fullstack SWE (402 on direct fetch, partial via LinkedIn/YC)
  3. www.ycombinator.com/companies/sepal-ai · 2026-06-07, YC S24 profile: founded 2024, SF, team size 15, founders Robi Lin/Kat Hu (ex-Turing)/Fedor (ex-Vercel), Fortune 500 + AI-lab customers, status acquired
  4. www.orrick.com/en/News/2026/02/Mercor-Acquires-Sepal-AI · 2026-06-07, Acquisition announcement, 2026-02-06; Mercor acquires Sepal AI; no deal terms disclosed
  5. www.crunchbase.com/organization/sepal-ai · 2026-06-07, Crunchbase profile (403 on fetch; via search) - funding & investors
  6. www.crunchbase.com/funding_round/sepal-ai-pre-seed--fda22c6a · 2026-06-07, Pre-seed round dated 2024-09-25, ~$500K
  7. startupintros.com/orgs/sepal-ai · 2026-06-07, Investors: Metaplanet Holdings, SID Venture Partners, Sterling Road, Team Ignite Ventures, YC
  8. www.linkedin.com/company/sepalai · 2026-06-07, Public snippet: HQ San Francisco, 51-200 employee band (likely incl. contract experts), Technology/Information/Internet
  9. www.hud.ai/case-studies/sheetbench-50 · 2026-06-07, SheetBench-50 financial-analyst benchmark co-built by HUD and Sepal AI; tasks validated by finance pros from PwC, Cisco, Charles Schwab, Fannie Mae
  10. huggingface.co/datasets/hud-evals/SheetBench-50 · 2026-06-07, SheetBench-50 dataset hosted on HuggingFace under hud-evals
  11. getlatka.com/companies/sepalai.com · 2026-06-07, Third-party unverified claim: ~$2M revenue, 13-person team, 2024
  12. pitchbook.com/profiles/company/639950-14 · 2026-06-07, PitchBook profile (valuation/investors/acquisition) - via search snippet
Last updated 2026-06-07 · Every quantitative field carries a source and a confidence tag. Fields we could not source publicly are marked unknown, never estimated. See the methodology.