Dan Posch
About Dan Posch
The one angel investment we could confirm is idler's seed round, announced in August 2026. Press coverage lists Dan Posch among the angel investors in that round.
We found no public record of other investments, check sizes or fund affiliations for him. Public profiles of people named Dan Posch belong to several different people, and we could not tie any of them to this investment, so this page does not attribute a career history to him.
idler raised a $9M seed round. FinSMEs reported it on August 21, 2026. Paradigm led the round, with participation from Y Combinator and Long Journey. Angels in the round included Manish Chandra, Catheryn Li, Dan Posch, Janine Leger, Lynett Capital, Feross Aboukhadijeh, Nur Bazylbekov and Smaiyl Makyshov.
idler is a San Francisco frontier data research lab and AI evaluation platform. It builds evaluation suites, programmatic datasets and reinforcement learning environments for AI labs, including long-horizon software engineering and cybersecurity testing environments. It launched ShelfLife, a public benchmark for autonomous agents, alongside the round. The company said it would use the funding to grow its machine learning research team, scale compute and build more reinforcement learning environments and evaluation datasets.
The only confirmed data point is a seed-stage investment in AI evaluation and reinforcement learning infrastructure. He has made no public statements we could find about stage preferences, sectors, geography, check size or what he looks for in founders.
- idler: San Francisco developer of AI evaluation platforms and reinforcement learning environments for frontier AI models. Dan Posch took part as an angel in its $9M seed round in August 2026.
Investing activity
Dan Posch appears in 1 AI deal tracked by the Lounge deals desk. The rounds are mostly Seed, with a median round size of $9M. The most recent is idler (Seed, $9M, Aug 2026).
Dan Posch most often invests alongside Paradigm, Smaiyl Makyshov, Lynett Capital and Feross Aboukhadijeh, and the companies they back on Lounge are mostly in AI.
Deals
Frequently asked questions about Dan Posch
Has Dan Posch invested in AI startups?
Yes, one investment is confirmed. He is listed as an angel investor in idler's $9M seed round, announced in August 2026 and led by Paradigm.
What stage does Dan Posch invest in?
The only confirmed investment is a seed round. We found no public statement from him about his preferred stages.
What is Dan Posch's typical check size?
Not public. The idler announcements gave no individual investment amounts, and we found no statement from him on check size.
Who else invested in idler's seed round with Dan Posch?
Paradigm led the round, with Y Combinator and Long Journey. Other angels included Manish Chandra, Catheryn Li, Janine Leger, Lynett Capital, Feross Aboukhadijeh, Nur Bazylbekov and Smaiyl Makyshov.
How can founders contact Dan Posch?
We could not confirm an official LinkedIn, X or personal site for this investor. Founders should look for a warm introduction through co-investors or the companies he has backed.
Is Dan Posch an angel investor?
Yes. Dan Posch invests personally as an angel.
What AI companies has Dan Posch invested in?
Dan Posch's AI investments include idler. The 1 round on Lounge are listed on this page with amounts, dates and co-investors.
What stage does Dan Posch invest at?
In the rounds tracked on Lounge, Dan Posch has invested at Seed, with a median round of $9M.
Who does Dan Posch co-invest with?
Dan Posch's most frequent co-investors on Lounge are Paradigm (1 deal), Smaiyl Makyshov (1 deal), Lynett Capital (1 deal), Feross Aboukhadijeh (1 deal) and Y Combinator (1 deal).
How can founders reach Dan Posch?
Founders on Lounge can see Dan Posch's contact details in AI Investor Contacts (paid plans), check for a warm introduction through members who worked with them under Warm Paths, and add Dan Posch to their Investor Pipeline to track the conversation.