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14,448 startups · 29 programs

hillclimb

Active · Training Data for Recursive Self-Improvement

WebsiteYC profile

Why it ranks

How the rank works
8signal of 100 · rising 7
  • went through YCProgram · this site+4
  • team of 4Team size · YC's directory+3.6

A sum of public facts, not a judgement and not investment advice.

Competitors

AICashew LabsShared: recursive self, self improvement, trainYC X25San FranciscoStartup →AIZettascale ComputingShared: recursive self, self improvement, frontierYC S24San FranciscoStartup →AIJigsawShared: recursive self, self improvement, training dataspeedrun SR005San FranciscoStartup →AIMonteShared: recursive self, self improvement, reinforcement learningYC S25San FranciscoStartup →AITwolabsShared: recursive self, self improvement, training dataYC X26San FranciscoStartup →OtherSnorkel AIShared: training dataStartup →
Companies closest to hillclimb
Company
Cashew LabsShared: recursive self, self improvement, trainYC X25ActiveAI, Devtools
Zettascale ComputingShared: recursive self, self improvement, frontierYC S24ActiveAI, Devtools
JigsawShared: recursive self, self improvement, training dataspeedrun SR005Not statedAI, Data
MonteShared: recursive self, self improvement, reinforcement learningYC S25ActiveAI, Devtools
TwolabsShared: recursive self, self improvement, training dataYC X26ActiveAI, Devtools
Snorkel AInot in a program hereShared: training dataElsewhereOther

Adjacent

AIOoak DataShared: training data, reinforcement learning, workYC S26San FranciscoStartup →OthermeerchatShared: self improvementAntlerPortugalStartup →AIMaxinsightsShared: training dataSPC 2025San FranciscoStartup →AIHubShared: training data, frontier, labsYC X26San FranciscoStartup →AIAcquiredSepal AIShared: training data, reinforcement learning, labsYC S24San FranciscoStartup →
Companies next to hillclimb
Company
Ooak DataShared: training data, reinforcement learning, workYC S26ActiveAI
meerchatShared: self improvementAntler Not statedOther
MaxinsightsShared: training dataSPC 2025Not statedAI, Devtools
HubShared: training data, frontier, labsYC X26ActiveAI, Data, Devtools
Sepal AIShared: training data, reinforcement learning, labsYC S24AcquiredAI, Data

Also from F25 in AI

All of F25
AICortex AILarge-scale real-world robot & human data for embodied AIYC F25San FranciscoStartup →AISpecific LabsReal World Environments and Data for AIYC F25San FranciscoStartup →AIInactiveSylvianSpecialized AI Agents.YC F25San FranciscoStartup →AIAbsurdThe production canvas for AI film teamsYC F25Los AngelesStartup →AIAirCaps AIVoice AI that hears what other models miss.YC F25San FranciscoStartup →AIAlderAI employees for finance, starting with accounts receivable.YC F25San FranciscoStartup →
Company
Cortex AILarge-scale real-world robot & human data for embodied AIteam of 3ActiveAI
Specific LabsReal World Environments and Data for AIteam of 7ActiveAI
SylvianSpecialized AI Agents.team of 2InactiveAI
AbsurdThe production canvas for AI film teamsteam of 10ActiveAI
AirCaps AIVoice AI that hears what other models miss.team of 5hiringActiveAI, Devtools
AlderAI employees for finance, starting with accounts receivable.team of 2hiringActiveAI

Founders

  • Jun ParkFounder/CEO

About hillclimb

We work with frontier AI labs to help train their agents to become AI research scientists

YC batch
F25 · Fall 2025
Status, per YC
Active
Category
AI, Developer tools
Team size
4
Location
San Francisco, CA, USA
Founded
2025
Checked
13h ago

YC tags: Reinforcement Learning

Changes seen

HiringSep 28, 2026

Stopped hiring.

Source ↗

hillclimb in F25: 146 companies, 88% AI

LinkedIn

hillclimb: questions

Which YC batch was hillclimb in?

hillclimb was in Y Combinator's Fall 2025 batch (F25).

Is hillclimb still active?

Y Combinator lists hillclimb as active.

Who founded hillclimb?

hillclimb's founders, as listed on its YC page: Jun Park (Founder/CEO).

Where is hillclimb based?

hillclimb lists San Francisco, CA, USA as its location on YC's directory.