Web Development Startups funded by Y Combinator (YC) 2026

Inth monitors your pull requests, codebase and website to catch privacy issues and turns them into fixes and evidence. Every product change you make exposes you to privacy risk. Customers lose trust. Fines and lawsuits are given. Fundraising and customer deals are broken. New market launches halt. The growth you thought you would have slows because privacy compliance is overwhelming and changes with every product update. Inth is fixing this to help you automate privacy compliance to ship and grow faster. Inth scans your PRs, website and codebase to catch any privacy risk. It then fixes and evidences them against your product, policies and global privacy laws to automate privacy compliance in every region your customers are in. Start a free privacy scan at: inth.com

Floot is the layer where vibecoded software runs. SaaS is dead. Hundreds of millions of people already spend their day in Claude or ChatGPT - and increasingly, when they need an app, they won't buy one. They'll describe it, and it will exist. We're building the infrastructure that makes that real. When Claude creates an app, it needs somewhere for that app to live: a backend, a database, hosting, a domain, the ability to scale, various services, maybe even to be able to work as a mobile app. Floot is that place - a full stack purpose-built for AI to operate, from a specialized framework that defines how AI writes and runs code, down to scalable hosting on AWS. This means you can now build and ship real apps directly inside Claude and ChatGPT. Connect Floot, and the model you already pay for writes and debugs the code, shows a live preview, and publishes to your own domain. No need to wire up git, vercel, supabase and a dozen other providers. And no AI credits - every message runs on the subscription you already have, because we charge for the platform, not for a token markup. We built Floot this way because we've watched the model layer commoditize - every serious builder writes good code now, including us. The lasting value isn't another agent between you and the model. It's the layer underneath, from wherever people already are. We're building Floot to be the home for all operation software, for the decades where most new software on earth is written by AI. ✨ Try it: floot.com

Wavedash uses cutting edge browser technology to let gamers play the latest releases with no downloads or installation.

assistant-ui helps frontend developers add AI chat to their apps. Our product is used by several dozen companies, like LangChain, Stack AI, Browser Use, and Athena Intelligence. We're building an open source Typescript/React library and a backend as a service, with first class integrations into popular agent frameworks like LangGraph and Vercel AI SDK.

Vibe enables everyone to turn their thoughts into real world apps through conversation. Let’s vibe code the future.

Pazi enables people to build agents that run all operations in a company. You create an agent for a position (eg. developer, devops, social media manager, SDR, etc.), you give it a goal (eg. reach 10k followers on X) and let it create a plan, start checking in with you, oversee how the goal is coming up.

Repaint lets you build professional websites by chatting with AI. It interviews you, researches you online, and generates a custom websites. Then you can edit anything by asking the AI. Our vision is to merge traditional website builders with AI coding tools, creating a new way for anyone to make more advanced software.

refine is an open-source, headless React framework for rapidly building enterprise web applications. It eliminates many repetitive tasks like ➡️ CRUD operations ➡️ State management ➡️ Routing ➡️ Authentication ➡️ Access Control ➡️ i18n and saves days of development time. So far, thousands of great projects have been built by 15,000+ monthly active refine developers. Use cases are ranging from admin panels, dashboards, and internal tools to B2B solutions and complex SaaS interfaces. refine is backed by a strong community featuring 16K GitHub stars ⭐️, 180+ contributors and 2,500 Discord members. Thanks to it's unique "Headless UI" approach, refine works with any custom design. It has also ready-made integrations with 4 most popular UI frameworks: Ant Design, Material UI, Chakra UI and Mantine. refine is totally backend agnostic and it can connect to 15+ backend services out-of-the-box, incl. custom REST & GraphQL API's. With refine, developers always have 100% control over their projects as they build, style and deploy the way they like.

Designbase is the interface design tool that gives early teams design and development superpowers. Create stunning interfaces, immediately available as code, regardless of resources.

Reflex is the operating system for building mission-critical enterprise applications. Today’s enterprise stack is fragmented. Shipping an app requires stitching together multiple tools and coordinating across multiple roles. Reflex replaces that complexity with a single, unified platform to build, deploy, and manage production applications end-to-end. We empower teams to own the entire lifecycle of their apps — from idea to production — without needing specialized infrastructure, DevOps, or platform teams. We do this by providing solid, reusable abstractions at both the framework and infrastructure layers. Because we own the underlying open-source framework and the platform it runs on, we can manage the full lifecycle of the application seamlessly. With Reflex, teams securely connect to company data, use AI to build standardized applications on top of our open-source framework, and deploy with a single click to share across their organization. We’re replacing the fragmented enterprise stack — and the organizational bottlenecks that come with it. Founded by Alek Petuskey and Nikhil Rao, Reflex has powered over 1 million applications, earned 28,000+ GitHub stars, and is used by 30% of Fortune 500 companies for internal tools and data-driven applications.

Bunting Labs researches and develops custom AI models for surveying and GIS.

Orca is an ADE built for engineers who run 10 to 100 coding agents at once. Termina-based. Any coding agent. Bring your own subscription (Claude Code, Codex etc). Mobile app included. Browser, CUA, Mobile emulator, and other. Minimal yet powerful. Includes CLI to let agents control it https://github.com/stablyai/orca

Awesomic matches companies with top & vetted product talents in 24 hours. Find your designers, engineers or no-coders in a few clicks. They deliver you results through our app, every 24 business hours guaranteed, for a flat monthly subscription. Successfully matched 4000+ companies, including 400+ YC startups, with their talents who completed over 14 000 projects in the app. Book a live demo here: https://www.awesomic.com/demo Portfolio – https://www.awesomic.com/portfolio Cases – https://www.awesomic.com/case-study

Whalesync makes data syncing easy. Our automation platform syncs data between key business tools like Webflow/Wix/WordPress and Airtable/Notion/Google Sheets. We give marketing teams two-way, real-time sync, so they can manage their website from their favorite collaboration tools. Whalesync launched during Y Combinator’s S21 cohort. Since then we’ve raised from some of the world’s top investors. We’re now trusted by hundreds of companies like [Ramp](https://ramp.com/), [Webflow](https://webflow.com/), and [Alchemy](https://www.alchemy.com/), and process millions of transactions every day. Many of our customers enjoy the product so much they [tell all their friends](https://whalesync.com/customers).

WeWeb is a visual programming tool that allows you to build user interfaces on top of existing databases & auth systems. It allies the short learning curve of no-code with the freedom of code. CONTROL & FREEDOM – Build pixel-perfect frontends with drag-and-drop UI elements and no-code CSS properties but have the option to add custom code or import your own Vue.js components. CODE BEST PRACTICES – Follow development best practices by building components, global workflows and re-usable functions with no-code triggers and formulas with the option to add custom JS where needed. NO VENDOR LOCK-IN – WeWeb generates a standard PWA-ready Single Page Application and allows you to deploy your projects on your own infrastructure. Build in no-code, host on-premise.

The Sails Company was founded by the original author and maintainers of the Sails framework. In addition to free and open-source software, The Sails Company offers a full-service web & mobile studio and professional support for the tools we maintain.

React components to build charts and dashboards

What if you could build web apps as easily as you make a Figma design or edit a Google Doc? Enter Mocha. We've reimagined app development with a state-of-the-art coding agent that builds for our users. Want to launch that app idea? Need to build something for your community? Looking to prototype faster? Start here. We've removed the barriers between idea and execution. Our mission is to empower everyone to build for the web, our vision is personal software.

At Aptible, we envision a world where developers achieve more with less infrastructure. We’re building the platform that empowers developers at companies of all stages of development to move beyond the traditional method of managing infrastructure—DIY with expert infrastructure and platform engineers on AWS, GCP, or Azure. We’ve done this through our secure, compliant, reliable, and scalable Platform as a Service that’s been used by thousand of developers, hundreds of companies, and dozens of publicly traded and unicorn companies since 2013.