Nalu Concepcion is a Co-Founder at Idler (YC S25), a frontier AI data research lab building the evals and reinforcement learning environments used by the world's leading AI labs to measure and train their models.

Nalu studied Computer Science at Cornell University and built a diverse tech career spanning software engineering at Microsoft, product roles at Poshmark, and data science at PayMongo (YC S19).

Nalu brings a rare blend of engineering depth and operational instincts, having gone from orchestrating 500+ person events to scaling complex RL environments for frontier model labs.

Idler, co-founded with Ivan Chub and Tony Goss in 2025, raised a $9M Paradigm-led seed round with participation from Y Combinator, Long Journey Ventures, and notable angel investors including Poshmark founder Manish Chandra.

In its first year, Idler developed thousands of coding evals and environments for a top frontier lab, with the client's models improving eightfold at long-horizon coding tasks during that period.