About
About RL List
RL List is an open directory of the companies building reinforcement learning environments — the simulated, resettable settings where AI agents are trained and evaluated. As reinforcement learning became the center of frontier model development, the list of companies building these environments grew faster than anyone was tracking it. RL List exists to track it properly: who's building what, for whom, and how they compare.
§ Methodology
How we rank
Only companies whose primary product is RL environments, simulators, or evaluation harnesses are eligible for the ranking. Adjacent businesses — human-data labelers, expert marketplaces, and generalist AI services firms — are listed for context but sit outside the ranked list, even when they also sell environments. Eligible companies are scored on the same public, three-part rubric: growth & momentum (50%), traction & credibility (35%), and accessibility (15%). The weighted total sets the order. There are no sponsored placements and no pay-to-rank. Where a fact isn't publicly confirmed, we mark it rather than guess, and every profile carries a correction link.
§ Maintainer
Who maintains it
RL List is maintained by the team at Huzzle Labs, which builds RL environments, RLHF datasets, and evaluation benchmarks. Huzzle Labs is listed in the rankings and scored on exactly the same rubric as every other company — no exceptions, no thumb on the scale. We think a directory is only useful if it's honest about its own position in it.
§ Contribute
Get listed or suggest a change
Building RL or evaluation environments and not on the list? Or see something that needs fixing? Email us at pratik@huzzle.app and we'll review it against the rubric.