Y Combinator Summer 2026 (S26) Companies

Executor is a tool that normalizes API integrations from different protocols (MCP, OpenAPI, GraphQL, or custom) into a single uniform tool shape, letting AI agents call any tool through one interface with a sandboxed TypeScript runtime. It targets developers and teams building agent-based applications, offering per-user credentials, call tracing, and safety guardrails for destructive actions, available as cloud, desktop, and CLI options.

2 investors

Exosat designs and builds low-Earth-orbit satellite constellations for sovereign operators, offering direct-to-cell, IoT, and broadband connectivity. It uses ITAR/EAR-free supply chains to let operators lease network capacity or buy turnkey constellations, serving enterprise customers across sectors like maritime, aviation, logistics, and agriculture.

4 investors

An applied AI research lab that develops world models enabling agents to simulate physical environments with high-fidelity reconstruction, using technology derived from autonomous vehicle systems.

3 investors

Fabraix develops automated security testing software that probes AI agents for vulnerabilities using adaptive attack techniques, enabling companies to continuously validate the safety of customer-facing AI systems without manual penetration testing.

3 investors

Familiar builds an AI video-translation and dubbing model that combines voice cloning and full-face lip-sync in a single system, preserving tone, expressions, and background audio, with support for real-time streams. It offers an API, an MCP server for agents, and a self-serve dashboard for creators and platforms translating video into multiple languages.

3 investors

Financial Datasets provides institutional-grade market data infrastructure designed for AI agents, offering an API for real-time and historical stock data, fundamentals, and text extracted from SEC filings. Its data is verified against source documents like SEC filings, earnings releases, and transcripts for use in financial analysis and research workflows.

3 investors

Floracene provides independent surgery centers with software to identify lower-cost clinically equivalent orthopedic and spine implants based on their existing manufacturer contracts. The platform helps physician-owners reduce implant costs by presenting alternative options that meet clinical requirements for specific procedures.

1 investor

Florin is a private financial membership offering accounts, cards, and treasury services.

2 investors

FlowManual is a back-office platform for construction contractors that analyzes bids, contracts, vendor quotes, and invoices to identify scope, price, and exclusion changes before work begins. It flags discrepancies on exact contract lines with cost impact rankings to prevent costly oversights during project execution.

1 investor

Frontier Computing grows lab-cultured biological neural networks at large scale to serve as a training substrate for machine learning, colocating memory and compute to support training of large-parameter models. The company targets applications such as long-horizon language reasoning as an alternative to conventional silicon compute clusters.

4 investors

GAMGEE develops personalised mRNA cancer vaccines for dogs, created from the animal's own tumour tissue to help its immune system fight the cancer. The company manages the full process end to end—from diagnosis and tissue sampling with the pet owner's vet, to genomic analysis and treatment delivery via veterinary oncologists—and is currently running clinical trials in Australia while accepting applications globally.

2 investors

GitCafe is a git forge for hosting code, reviewing changes, and shipping software, including its own git implementation and a first-party CLI for managing pull requests and credentials. It is aimed at software developers and offers free private repositories during its beta.

3 investors

Glen provides a shared source of truth platform where teams and agents access and contribute to consistent information, reducing contradictions and enabling fact-based decision-making across different departments.

2 investors

Graphify is an open-source, on-device tool that maps a code repository into a local knowledge graph (graph.json, graph.html, GRAPH_REPORT.md) using tree-sitter grammars, letting AI coding assistants query real paths through the code instead of grepping. It installs as a skill across 17 assistants (including Claude Code, Cursor, Copilot, Codex, Gemini CLI, and Aider) and serves the graph via an MCP server for developer teams.

5 investors

Greypoint Industries manufactures affordable autonomous interceptor systems designed to counter drone swarm attacks, offering military forces a cost-effective defensive solution that can be deployed and operated by soldiers.

1 investor

Grip Robotics develops physical-AI grippers that perceive, adapt, and manipulate objects in the waste stream, automating handling tasks in waste management that currently rely on manual labor.

1 investor

Grocalo builds an AI platform that analyzes creators' audiences through video understanding and platform analytics to personalize and distribute content to their specific followers. It serves content creators and public figures looking to grow their audience and reach across social platforms.

1 investor

GUILD operates as a defense contractor that manufactures aerospace components while using AI systems to connect and optimize the contracting, manufacturing, and delivery process across requirements, pricing, supplier management, and compliance.

3 investors

GutGutGoose sequences a customer's gut microbiome, then compounds personalized probiotic formulas of 8-20 strains matched to their individual gut, diet, health history, and metabolic pathways, with a retest at 90 days to measure colonization. The consumer subscription product is sold in the US and Australia.

2 investors

Hardware Intelligence builds an agent-native toolchain for chip design, starting with Wave, an agentic waveform debugger for terminal use.

2 investors

Hebbian Robotics builds open-source SDKs and data-quality infrastructure for Physical AI data pipelines, helping robotics foundation model labs filter, label, and curate large volumes of egocentric video data. Its tools let data teams write quality checks as Python functions with durable execution, observability, and auditability.

2 investors

Hera reviews mechanical engineering drawings (prints) automatically, checking parts against current drawings and catching missed callouts in minutes rather than the days senior engineers spend reading prints by hand. It targets manufacturing and industrial teams, keeping the review process auditable and on-premises.

1 investor

hiloop provides snapshottable, forkable compute infrastructure with built-in observability for AI agents that propose, run, and verify experiments (autoresearch). It offers self-provisioning sandboxes via API, brokered secrets, and per-run tracing with token and cost tracking queryable via SQL, aimed at teams doing autoresearch, model training, and performance-critical development.

4 investors

Hilstart provides an AI agent and a hardware interface device called Tracer that automate electronics board bring-up, firmware development, and design validation on real hardware. It serves hardware engineering teams, generating and running approved test plans, driving instruments, and writing results back to their tracker via API, usable in the cloud or from the user's own environment.

1 investor