Y Combinator Fall 2025 (F25) Companies

Semiotic develops AI agents that automatically create landing pages for startups, addressing the gap between poor-quality automated website builders and expensive agency services.

1 investor

SF Tensor builds software and infrastructure for high-performance AI and HPC workloads, offering automatic kernel optimization and cross-cloud compute management to reduce costs and complexity for research teams. The company provides Tensor Cloud (managed GPU orchestration), a Kernel Optimizer, and the Emma programming language to abstract hardware differences while maintaining performance.

1 investor

Sol is a browser-based IDE that allows developers to run multiple coding agents in parallel within organized tabs, tabs, and workspaces, eliminating context switching between documentation, dashboards, and code terminals.

1 investor

Sorce helps job seekers discover positions by swiping through opportunities, with automated application submission powered by AI.

1 investor

Soren builds custom, domain-specific AI systems for regulated and mission-critical organizations, rather than relying on general-purpose models. The company develops AI solutions deployed within clients' existing infrastructure that encode business-specific context and workflows.

1 investor

Sourcebot provides a code search and context layer tool for coding agents and development teams, allowing rapid search across multiple repositories and integration with AI agents for tasks like code understanding and context gathering.

3 investors

Specific builds infrastructure software for AI coding agents, enabling them to run, deploy, and maintain the code they generate with tools designed for AI-native workflows rather than human developers.

1 investor

Specific Labs captures real workflow data and processes for training dependable AI agents, serving frontier labs and enterprises.

1 investor

Structured uses AI and computer vision to automatically review architectural and engineering drawing packages, checking for compliance violations, coordination conflicts, and scope gaps across disciplines including architecture, structural, MEP, and civil engineering.

2 investors

Sunflower Sober operates a digital community and support group for people pursuing sobriety, enabling peer connection and shared recovery journeys.

2 investors

Sylvian provides tools for organizations to create AI agents tailored to specific business tasks and workflows.

1 investor

Tell If AI builds autonomous content systems for brands, leveraging deep learning and multimodal AI technologies.

1 investor

Tensor operates fully autonomous factories that manufacture custom designs on-demand, 24/7, targeting unit-level production economics. The company serves manufacturers and businesses requiring rapid prototyping or short-run production.

1 investor

Terrain provides a go-to-market platform with AI capabilities designed for sales teams targeting businesses in physical industries such as construction and food service.

1 investor

The Context Company provides observability and monitoring software for AI agents, helping developers identify and fix user frustration, tool failures, and behavioral issues in agent systems. The platform integrates with popular AI frameworks and surfaces alerts on hallucinations, missed goals, and performance problems.

1 investor

The Hog is a web intelligence API that aggregates live data from multiple online sources into structured, ranked outputs for AI agents. It serves companies building research, sales enrichment, competitive intelligence, and GTM automation workflows.

1 investor

Thesis is an AI research lab that automates AI research and development through autonomous experimentation. It applies recursive self-improvement machine learning to problems in biology and materials science.

1 investor

Tornyol develops lightweight autonomous drones equipped with sensors and control software to target and eliminate mosquitoes. The technology aims to reduce the cost of mosquito control for urban pest management and disease vector elimination.

3 investors

Trelium builds AI agents that automate repetitive workflows for businesses, starting with custom merchandise and promotional product teams. The company helps businesses scale by reducing manual work and improving operational efficiency.

1 investor

Unsiloed builds AI models that read and analyze document pages using attention-guided heatmaps to identify and extract structured data from tables, figures, and text regions. The product serves organizations that need to process complex multi-page documents and extract information while preserving hierarchical relationships.

2 investors

Uplane is an AI-powered platform for performance marketing that automates the generation of personalized ads and landing pages, campaign launches, and budget allocation across channels. The platform serves marketing teams seeking to improve campaign results while reducing time, effort, and ad spend.

2 investors

Velvet creates datasets and evaluations for training multimodal AI models, serving AI labs and enterprises building systems with improved spatial reasoning and latency performance.

1 investor

Veria AI is an autonomous pentesting platform that identifies and exploits security vulnerabilities across code repositories, then generates fix recommendations. It integrates with developer tools to surface exploitable flaws that automated reviews and human security teams typically miss.

3 investors

Wardstone designs and plans to deploy a constellation of satellites equipped with sensors and kinetic interceptors to detect, predict, and counter hypersonic and ballistic missiles for U.S. military defense agencies. The system, called the Golden Dome, is intended to provide global missile defense capabilities across multiple domains of conflict for the Space Force, Air Force, Navy, and Missile Defense Agency.

1 investor