Y Combinator Summer 2026 (S26) Companies

Hera provides automated review of mechanical engineering drawings, checking against ASME and ISO standards to identify dimensional, tolerance, and GD&T violations before manufacturing. The tool is used by engineer-to-order manufacturers in aerospace, medical devices, and pressure vessel production to accelerate release cycles and reduce costly manufacturing errors.

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.

1 investor

Hop Aero develops rocket-based cargo delivery systems designed to transport supplies to remote or contested locations at high speeds, primarily serving U.S. military and allied defense applications.

1 investor

Hoplite provides infrastructure for deploying and managing software factories in cloud environments.

1 investor

Hubble provides an intelligence layer for patient information, reaching EHRs, payers, and patient records through APIs, browser, and voice to return a single normalized record with source traceability and audit trails. It offers data infrastructure for digital health companies and a no-code workflow studio for operations teams automating manual tasks.

1 investor

Hyperprobe provides an SDK that enables AI coding agents to capture runtime state from running services for production debugging. The platform allows developers to set live breakpoints and inspect variable values without pausing threads or redeploying code, working with tools like Cursor, Claude Code, and Codex.

1 investor

Illume Labs aggregates data from wearables, blood tests, and genomic sequencing to deliver personalized health insights via text message and conversational AI, helping users understand changes in their health metrics and receive actionable recommendations.

1 investor

IMPACT builds a containerized counter-drone defense system that autonomously detects, launches, and intercepts hostile drones, pairing two interceptors: HUNTER for close-range low-altitude threats and SABLE for fast, long-range movers. It targets protection of high-value sites such as data centers, power substations and plants, and airports.

1 investor

Induction Labs is a research lab developing foundation models designed to learn from their own observations and update over time, with the goal of scaling curiosity-driven artificial intelligence toward superintelligence. It positions itself in the AI research and foundation model space.

1 investor

Inkbox provides an identity layer for AI agents, enabling them to have email, phone, iMessage, and internet addresses for communication and interaction.

1 investor

Instance Labs provides verification software that evaluates whether robots have successfully completed assigned tasks from camera footage. The platform helps robotics companies validate training data and accelerate policy development by analyzing raw video episodes and returning success verdicts with evidence.

1 investor

Instaplay is an AI-powered platform that generates playable multiplayer and solo games from natural language text prompts, without requiring traditional game engine setup. It enables users to create party, competitive, cooperative, and local multiplayer games that can be immediately played and shared via link.

1 investor

Insurf provides a managed workflow platform for healthcare providers to prepare and submit prior authorization requests and denial appeals. The platform handles source-cited drafting, physician review coordination, and submission tracking, serving Medicare Advantage and other health insurance programs.

1 investor

Isengard Industries manufactures production systems that enable allied nations to domestically produce precision-strike and counter-unmanned aircraft systems at scale and lower cost than traditional defense contractors.

1 investor

Kara engineers single-crystal diamond, handling growth in its own reactors as well as processing and characterization in-house. Its diamond materials target thermal management, power electronics, quantum sensing, photonics, quantum networks, and characterized research substrates.

1 investor

Kebra provides field service companies with AI-guided documentation and job capture tools that turn technician work into organized records, warranty claims, and parts orders for back-office processing. The platform aggregates job data over time to build institutional knowledge from field expertise.

1 investor

Lamb Labs develops custom silicon chips and a post-training technique that converts existing language models to a diffusion-based architecture for faster AI inference at lower power. It targets developers and companies running large language model workloads in the AI hardware and infrastructure space.

1 investor

Last Accounting Company (LAC) offers a combined accounting service and AI platform, using its agent "Björn" to automate manual bookkeeping while human accountants review the results, replacing tools like Procountor, Fennoa, and Netvisor. It handles bookkeeping, invoices, payroll, VAT and tax filings, monthly closes, and financial statements for startups and SMBs, with data sources connecting into its general ledger and accessible via an MCP server for AI agents.</parameter> <parameter name="founders">[]

1 investor

LATO conducts commercial diligence for investors by sourcing and interviewing domain experts and customers, then combining interview data with public and proprietary documents to create market simulations. The platform helps investors research companies and markets to inform investment decisions.

1 investor

LemonLime builds a data processing layer that converts unstructured, real-world business data into formats that AI systems can reliably work with, bridging the gap between messy operational environments and AI-ready information streams.

1 investor

LevoCred provides AI-powered software for managing structured credit operations, serving credit funds and loan originators. The platform automates loan analysis, compliance monitoring, and report generation workflows.

1 investor

Libra Robotics builds autonomous robots for solar farm installation at utility-scale and commercial projects. The company serves electrical contractors, equipment manufacturers, and solar project developers.

1 investor

Litmus is a hiring platform that evaluates software engineers through practical assessments aligned with how modern engineering teams actually work, replacing traditional interview processes.

1 investor

Justinian is an AI company that develops government affairs software to help companies monitor regulations, lobby policymakers, and win government contracts. The company rebuilds partnerships between government and industry solving critical problems.

1 investor