Y Combinator Fall 2026 (F26) Companies

Hopper offers fast inference infrastructure for voice applications, letting customers swap in open models such as Gemma-4 in place of GPT-4.1 and qwen3-tts in place of ElevenLabs for lower cost and higher speed. It serves developers and companies building voice and language-based products.

2 investors

Ignition Benefits is an employee benefits brokerage that uses AI to run its sales and back-office operations, helping companies with fewer than 200 employees manage health insurance costs. It serves small and mid-sized employers in the employee benefits and health insurance industry.

2 investors

Inflection Space Systems operates high-volume factories designed to produce tens of thousands of spacecraft per year. It supplies commercial and government customers in the space industry.

1 investor

Lambda Robotics develops autonomous robots for data centers and facilities that support AI compute operations. The robots are deployed into physical environments and improve through repeated deployments.

1 investor

Lantern offers an AI hiring manager that learns a company's definition of an exceptional hire, tests roles against the talent market, and then sources, interviews, assesses, and schedules candidates. It combines calibration, talent intelligence, candidate outreach, AI interviews, technical assessments, and scheduling in one system so teams do not need a separate ATS or sourcing tool.

1 investor

Lark develops AI agents that automate manual workflows for wholesale distributors, integrating with their existing ERP systems and learning from each distributor's historical data and team decisions. The agents are designed to handle operational tasks across a distributor's business.

1 investor

Lightfield is an AI tool for in-house legal teams that handles legal work automatically and integrates with email, messaging, CRM, and workflow systems. It connects to platforms such as Gmail, Outlook, Microsoft 365, Teams, Slack, Salesforce, Jira, ServiceNow, Ironclad, Zendesk, and HubSpot.

1 investor

Lyon trains a foundation model from scratch on a company's own customer event data, producing per-customer embeddings that power downstream predictions such as churn, credit risk, fraud, collections, income, and cross-sell. The model runs inside the customer's own cloud (AWS, GCP, or Azure) with the customer owning the weights and keeping data isolated.

2 investors

Maritime provides cloud infrastructure for running AI agents, giving each agent its own isolated, persistent virtual computer while handling hosting, scaling, and sleep/wake automatically. It serves companies and developers that need to deploy and manage large numbers of AI agents without maintaining their own infrastructure.

2 investors

Micora produces palletized, shippable solar microgrid systems that can be assembled without specialized labor, autonomously building 100kWp of capacity per day and scaling to utility-scale megawatt deployments. It targets customers with large, fast-growing power needs such as data centers, advanced manufacturing, and electrification projects.

1 investor

Mirrors offers regression testing for AI agents by reconstructing the internal tools and APIs an agent uses from production traces, then replaying real sessions against each code change to flag differences in tool calls, arguments, and resulting state. It runs in CI on every pull request and targets teams whose agents perform irreversible actions such as issuing refunds, updating records, or sending outbound email.

1 investor

Nodus Compute provides an execution layer for running AI workloads.

1 investor

Nxtcure Labs operates an AI-based, full-stack contract research organization (CRO) that helps move therapeutics from discovery through to market, alongside a mobile platform that guides cancer patients through treatment. It serves pharmaceutical and biotech drug developers as well as patients in the healthcare and drug discovery sector.

1 investor

Oasive is a platform for bond investors that combines research, screening, analysis, valuation, and reporting to support buy and sell decisions, automating tasks typically handled by analyst teams. It currently covers mortgage-backed securities and macro research, with plans to expand into municipal bonds, rates, asset-backed securities, and corporates.

1 investor

OnePatch offers an AI-based site reliability engineering tool that instruments production services, monitors their behavior, detects incidents, and works to resolve them through to a shipped fix. It is aimed at engineering and operations teams responsible for on-call and service reliability.

1 investor

Orca Aerospace develops onboard AI systems that operate spacecraft directly from the vehicle, using large language models paired with deterministic tooling to make mission-level decisions while keeping execution controlled by safety-focused systems. It serves the satellite and spacecraft operations market.

2 investors

ORO AI operates an open benchmark and evaluation platform for shopping agents, where developers submit agents that independent validators test against daily-changing tasks, with results feeding back as training data. It serves builders of agentic commerce systems.

1 investor

Papaya is an optimization platform that connects to AI agents via SDK, analyzes production traces across context, prompts, prompt caching, subagents, and tool calls, and delivers ranked recommendations—pushed to production as pull requests once approved—to improve agent quality, latency, and cost. It serves engineers building and maintaining AI agents.

1 investor

Perit.AI operates a platform that combines expert-led data and reinforcement learning to support AI labs in developing their models.

1 investor

A research lab building AI models trained to decode physical-world signals from instruments and to operate those instruments, using real-world measurement as the training signal rather than text corpora. It positions itself in machine learning and deeptech applied to physical sensing.

1 investor

Quippy is an app that provides a personalized, adaptive program for practicing social interactions through voice or text role-play with live feedback and targeted drills. Aimed at people looking to improve their conversational skills and social life, it delivers a structured 12-week curriculum built around each user's specific weaknesses.

1 investor

Redoubt is a Utah-based independent commercial insurance agency serving small businesses nationwide, with a focus on contractors, service providers, and trucking companies. It helps clients compare carrier and wholesaler options and handles coverage such as general liability, commercial auto, workers compensation, cargo, and DOT filings.

1 investor

RunInfra benchmarks machine learning models and serving engines across different GPUs, provides real performance measurements (latency, throughput, cost), and delivers a deployment-ready kit that runs on the user's choice of cloud infrastructure. The platform serves machine learning engineers and teams building inference workloads who need transparent, portable model deployment options.

1 investor

River is developing an AI-powered desktop environment aimed at increasing the productivity of knowledge workers, applying to general office and information tasks the kind of AI assistance already used in software development.

1 investor