# Jamesin Seidel

> Jamesin Seidel is a startup investor at Chapter One (London). See 0 investments, check sizes, portfolio. Updated Aug 2026.

- Type: Angel Investor
- Fund: [Chapter One](https://shizune.co/investors/profile/chapter-one-ventures)
- Location: London, United Kingdom
- Last updated: Aug 2026
- LinkedIn: https://www.linkedin.com/in/jamesin-seidel-5325b147/
- Website: https://x.com/seidtweets

Jamesin Seidel is a startup investor at Chapter One in London. Jamesin joined Chapter One's investing team in January 2022. She came into investing through the worlds of anti-spam, online safety, and professional sports betting.Before joining Chapter One, Jamesin was the tech lead for platform manipulation at Twitter. She focused on fake account detection, coordinated online harm, and electioninterference. Career highlights include developing algorithms to combat large-scale spam attacks, leading Twitter’s white hat investigations, and co-leading Twitter’s reporting on malicious automation and foreign interference during the 2016 Election for the Congressional Hearing. Prior to Twitter, she was a professional fantasy sports bettor working under Haralabos Voulgarious, using data and automation to get an edge in the sports betting market. Beyond work, Jamesin can be found on the poker tables and playing Zelda.

## About Chapter One

VC Fund · Los Angeles, United States

The venture firm for product-driven companies

5 contacts available at Chapter One.

| Name | Title | Profile |
| --- | --- | --- |
| Alex Labossiere | Investment Partner | https://shizune.co/investors/profile/alex-labossiere |
| Anand Iyer | LP | https://shizune.co/investors/profile/anand-iyer |
| Doug Dyer | CFO & COO | https://shizune.co/investors/profile/doug-dyer-a1f0 |
| Jamesin Seidel | Investment Partner | https://shizune.co/investors/profile/jamesin-seidel-bc27 |
| Jeff Morris Jr. | Founder & Managing Partner | https://shizune.co/investors/profile/jeff-morris-jr |

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