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Fedor Paretsky

Co-founder (technical), Sepal AI; now working on RL environments at Mercor · Sepal AIformer

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Technical co-founder of Sepal AI; after the Mercor acquisition his site says he is working on RL environments and links to Mercor.

medium confidenceBrooklyn, NYAt Sepal AI since 2024Updated 2026-09-19

Background

Early engineer at Vercel and Newfront, also worked at Mosaic (per his site and Fondo). Angel investor in One Small Step, a peer-support platform.

What they run now

RL environments inside Mercor (per his site).

Career

  1. 2026 – presentRL environments, Mercor
  2. 2024 – 2026Co-founder, Sepal AI
  3. —Engineer, Newfront
  4. —Early engineer, Vercel
  5. —Mosaic

Recent posts

2 posts archived · most engaged first, then the latest

Fedor Paretsky
working on something new in RL
•
Excited to be building a new company with my best friends! If you're looking to fine-tune a LLM for any advanced use-case, need a dataset, or are unsure how to get started, ping me! happy to help :) fedor@sepalai.com
10910 comments
All 2 in the feed →

Connections

Investments and boards

  • One Small Step (angel)

Who they amplify

Accounts whose posts Fedor has reposted recently: Sepal AI.

Why it matters here

Little direct relevance; an engineer on Mercor's environment stack.

How to reach

His site lists email and Signal as preferred contact; technical questions only.

What we could not establish
  • Exact Mercor title
  • Education

Sources

  1. Fedor Paretsky personal site
  2. Fondo: Sepal AI launches
  3. RL List: Sepal AI vendor profile
Also at Sepal AI
former

Robi Lin

Co-founder & CEO, Sepal AI (acquired by Mercor, Feb 2026); now at Mercor

former

Kat Hu

Co-founder, Sepal AI (acquired by Mercor, Feb 2026)