About
Josh Purtell is founder and CEO of Synth. Previously, he served as research scientist at Basis, an AI-powered accounting automation platform, and built machine learning infrastructure for cyber threat intelligence at Halborn following an acqui-hire of his startup Politeia. He holds an undergraduate degree in mathematics from Yale, where he conducted time-series machine learning research.
Josh @joshpurtell
Koan: T: GRPO is a trap S: But teacher, high variance is fine with enough rollouts T: True. GRPO is a trap S: But teacher, sampling task advantage directly is better than using a biased vf T: True. GRPO is a trap S: What about the algorithm is left? And he was enlightened
Aug 1, 2026 Β· β₯ 70 Β· β 3
Josh @joshpurtell
π https://t.co/Dos0R3927K
Jul 31, 2026 Β· β₯ 4
Josh @joshpurtell
Technically also possible, but not plausible: - they could do it, but prefer to let it happen and lobby a govt that hates them to solve the problem for them (to bizarre to be true) - they could prevent distillation, but this would unfairly punish a handful of legit Malay users
Jul 28, 2026 Β· β₯ 3 Β· β 2
Founder at SynthYC F24
Intro paths
Josh went through Y Combinator (Fall 2024) β any YC alum in your network can reach them through the YC community.
Their group partner at YC was Pete Koomen, General Partner at Y Combinator β the partner who ran Synth's batch and knows the company first-hand. YC profile β
In turn, Josh can intro founders to Synth's investors below.