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Osmosis

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Osmosis

Reinforcement Learning for AI Agents

osmosis.ai
1-10
B2B

Company research

Public company, workplace, funding, and market signals

Updated Jul 30, 2026

Overview

San Francisco-based YC W25 startup founded in 2024 by Kasey Zhang and Baiqing Lyu, building a forward-deployed reinforcement fine-tuning platform for AI agents and task-specific models that improve from real usage.

Primary product

Forward-deployed reinforcement fine-tuning / post-training platform for AI agents

Founded

2024

Headquarters

San Francisco, California, United States

Team size

1-10

Industry

Technology, Information and Internet

Sub-industry

AI infrastructure / reinforcement learning platform for agentic AI

Offices

San Francisco, California, United States

Business model

B2B SaaS
enterprise AI platform
AI infrastructure

Funding

Stage

Seed

Total raised

$6.8M

Latest round

Seed · Oct 2025

Latest amount

$6.3M

Seed

Oct 2025 · CRV and Audacious Ventures

$6.3M

Pre-Seed

Mar 2025 · Y Combinator

$500K

People & investors

Leadership

Kasey Zhang

Co-Founder & CEO

Baiqing Lyu

Co-Founder & CTO

Investors

Audacious Ventures
Bryant Chou
CRV
Erik Bernhardsson
Guillermo Rauch
Liquid 2 Ventures
Matteo Franceschetti
Misha Laskin
Paul Graham
Pioneer Fund
Sara Du
Shane Gu
Troy Demmer
Waseem AlShikh
Y Combinator

Work & culture

Technical, customer-facing, and hands-on; the company emphasizes bleeding-edge work, direct support with customers, high agency, and a paid in-person work trial in hiring.

Visa sponsorship

Limited

Compensation

Public hiring signals show full-time ML roles at $180K-$250K base salary in San Francisco; no public equity or bonus details were found.

Product & market

Pricing

Not publicly disclosed; appears to be sold as a B2B platform / enterprise software offering.

Differentiators

  • —Reinforcement fine-tuning for agentic AI rather than static prompt-only workflows
  • —Real-time / continuous retraining from production interactions
  • —Own-your-weights model export and self-host/VPC deployment
  • —Direct, hands-on support through the full post-training workflow
  • —Tool-use training and MCP-oriented workflows
  • —Designed for task-specific models that can beat foundation models on performance, cost, and latency

Technology

Python
FastAPI
Go
React
TypeScript
Next.js
Docker
Kubernetes
AWS Fargate
AWS SageMaker
PyTorch
DynamoDB
S3
LanceDB
Triton
Megatron-LM
SGLang
GRPO
DAPO
MCP

Customers

Fast-growing AI companies
Teams building AI agents
Engineering teams training task/domain-specific models
Customers needing reliable tool use, code generation, or domain-specific extraction

Competitors

OpenPipe
Databricks Mosaic AI
Scale AI
Modal Labs
LangSmith
Weights & Biases

Scale & contact

founders@osmosis.ai

Latest news

Cutting Memory in Long-Context RL with Fused Logprobs

Osmosis blog · Jun 2026

Describes a fused Triton logprob kernel that reduced RL training time and increased trainable context length for long-context reinforcement learning.

Training Thousands of LoRA Adapters at Once

Osmosis blog · Jun 2026

Explains a multi-LoRA/Megatron-Bridge approach that enabled thousands of concurrent LoRA adapter trainings and improved throughput.

Osmosis Raises $6.3M Seed Round for AI Reinforcement Fine-Tuning

Signalbase · Oct 2025

Reports the company’s $6.3M seed round and says the capital will be used to scale operations, expand engineering and research, and accelerate product R&D.

Applying RL: Improving Code Merging

Osmosis blog · Jul 2025

Introduces Osmosis-Apply-1.7B, an RL-tuned model for code merging that the company says outperformed larger foundation models on its validation benchmark.

Launch YC: Osmosis: Unlocking Real-Time Learning for AI Agents

Y Combinator

YC launch page describing Osmosis as infrastructure that lets AI agents learn from tasks in real time, with claims about accuracy, cost-efficiency, and fewer steps per task.

About / TeamBlogBook a demo / ContactCareersGitHub orgLinkedIn companyPlatformWebsiteX accountYC company page
SourcesOfficial homepageAboutPlatformBlogContactTermsPrivacy policyDPAYC company pageYC launch pageWork at a StartupGitHub orgLinkedIn company pageKasey Zhang LinkedInBaiqing Lyu LinkedIn

Jobs and careers at Osmosis

7 jobs at Osmosis

Medical Assessment and Content Editors

Remote
Content
Northeastern USA; Remote (North America); Western USA
1mo ago
Remote
Full-time
Apply

Clinical Content Editor - PGY-1/Medical Students

Remote
Medical Content
Remote (North America)
10mo ago
Remote
Full-time
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Panel Review Subject Matter Expert (SME)

Remote
Medical Content
Remote (North America)
10mo ago
Remote
Full-time
Apply

Osmosis Nursing Content Creator

On-site
Nursing Content
Anywhere
11mo ago
On-site
Full-time
Apply

Elsevier Clinical Content Reviewer, Specialty Specific (Part-Time, Fixed Term Contract). International (UK, AUS, NZ) Applicants Only

On-site
Medical Content
Anywhere
1y ago
On-site
Full-time
Apply

Elsevier Clinical Content Reviewer, Specialty Specific (Part-Time, Fixed Term Contract)

Remote
Medical Content
Remote (North America)
1y ago
Remote
Full-time
Apply

General Application

On-site
Open Application
Anywhere
1y ago
On-site
Full-time
Apply

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