Y Combinator Spring 2026 (X26) Companies

Ara is an autonomous coding agent that monitors development work, plans subsequent steps, and executes coding tasks using its own resources and memory to assist software teams in collaborative development.

2 investors

ReasonBlocks provides a runtime layer that optimizes AI agent performance by correcting reasoning processes and reducing token usage during execution, resulting in lower costs and improved reliability across repeated operations.

1 investor

Regbase provides regulatory monitoring and compliance tracking for lawyers, compliance officers, and business teams across employment law, AI governance, healthcare, privacy, government procurement, climate, private equity, and regulated industries.

1 investor

Rentahuman operates a marketplace that connects AI agents with human contractors to perform physical-world tasks. The platform serves as infrastructure enabling AI systems to interact with the real world through human intermediaries.

2 investors

Replicas provides a background coding agent that delegates development tasks to sandboxed coding environments, enabling developers to automate routine code changes and integration work.

1 investor

Result is an operating system that helps entrepreneurs start and run businesses, offering tools for app development, payments, marketing, customer support, business analytics, legal incorporation, product design, market research, performance optimization, fundraising, and integrations with third-party services.

1 investor

Revnu provides AI agents that automate growth, conversion, and retention tasks for early-stage software founders, handling SEO, ads, outreach, and customer retention so builders can focus on product development. The platform targets indie hackers, solo founders, and first-time builders looking to scale without hiring or agency costs.

1 investor

River Markets provides a unified trading terminal and API for prediction market desks, aggregating order books and execution across multiple prediction exchanges like Kalshi and Polymarket.

2 investors

Rudus is a software tool that automates takeoff and measurement tasks for concrete estimators, using AI to identify structural elements from construction plans and streamline the estimating workflow.

1 investor

Runtime provides a cloud platform for deploying coding agents that work with popular AI models across teams. The platform enables specialized agents for engineering, product, design, marketing, support, finance, and other departments to automate tasks like code generation, data analysis, and workflow automation.

1 investor

Saffron provides technical assessments for engineering hiring that evaluate how candidates work with AI coding tools. The platform captures and analyzes candidate interactions with code, AI prompts, and decisions to measure engineering competency in modern workflows.

1 investor

Saudara AI operates a brokerage platform that matches US brands with vetted overseas manufacturers for import orders, combining human brokers with AI tools that automate sourcing, quoting, quality control, logistics, and financing.

1 investor

Savant connects to existing business tools to consolidate scattered company knowledge into searchable, structured operating context for teams and AI agents. The platform captures procedures, workflows, and organizational expertise that AI systems need to operate correctly within a business.

3 investors

Sazabi builds an observability platform that uses AI to help engineering teams understand and control production systems. The platform is designed for fast-moving teams and aims to reduce manual monitoring, alert fatigue, and incident response overhead through conversational, intelligent interfaces.

4 investors

Scope is a platform that helps software products become discoverable and usable by AI agents through monitoring how agents interact with products, analyzing their behavior and errors, and recommending improvements. It targets product teams and businesses that want to ensure their products work seamlessly when used by autonomous AI agents.

3 investors

Sherpa uses behavioral data and continuous testing to automatically refine websites for both human visitors and AI agents, measuring success through conversion improvements.

1 investor

Shotwell.ai provides automated failure detection from video data for robotics companies, analyzing footage from both development and production environments to generate annotations with minimal latency.

1 investor

Silmaril is a security monitoring and threat detection platform that protects enterprise systems by identifying and blocking malicious tool calls and prompt injection attacks.

1 investor

Smartbase is an AI-native ERP system that automates end-to-end digital operations for manufacturers, including procurement, planning, inventory, orders, finance, and compliance. The system learns from existing supply chain behavior and automates tasks such as purchase order generation, production scheduling, inventory tracking, and financial reconciliation.

1 investor

Smol Machines provides a runtime system for executing workloads in hardware-isolated Linux VMs with an open-source engine, supporting development workflows, code sandboxing, and portable executable packaging. It targets developers and organizations needing secure isolation and portability of applications across different environments.

1 investor

Soria provides an AI-powered financial research platform that aggregates public and private data sources into continuously-updated models for sector-focused investors, initially targeting healthcare professionals at hedge funds, banks, and asset managers.

1 investor

StableBrowse sources, labels, and enriches real-world data for machine learning model training, focusing on hard-to-find datasets including enterprise workflows, egocentric video, and agent trajectories. The company serves frontier labs and AI research teams building large-scale models.

1 investor

Stage provides code review software that helps engineering teams understand and evaluate AI-generated code contributions. The platform accelerates the review process by reorganizing how developers analyze pull requests, allowing teams to review submissions more quickly.

1 investor

Standard Signal is a hedge fund that uses AI models with chain-of-thought reasoning to discover and autonomously execute trading strategies across equities, commodities, forex, and derivatives. The company develops explainable AI systems designed to identify market inefficiencies and outperform traditional quantitative approaches in real time.

2 investors