Design Tools Startups funded by Y Combinator (YC) in the San Francisco Bay Area 2026

Glue is an open source design editor for AI agents. It gives coding agents an infinite canvas to create new interfaces, iterate on existing ones, and turn those changes into production-ready code all in real time. The rise of coding agents is collapsing EPD into one role: builders. This new paradigm means design and engineering can now converge to a single workflow. Builders no longer want static mockups in one tool, and implementation in another. Glue is a collaborative workspace where builders and agents can create new components, iterate on existing interfaces, and implement as code. The same tight feedback loop that once made Figma powerful for designers is now built for builders and their armies of agents. Being open source allows us to penetrate workflows at zero cost and build trust quickly. Right now there are no design tools with AI as the primary user. Existing tools bolt on copilots as an afterthought. Soon, every company will have AI agents building their interfaces. We are building the surface for this workflow.

Inspector is the AI IDE for designers to ship to prod. Just select any element on your live front end, edit it like you would in Figma, and Inspector writes the changes straight to your codebase.

Rivet is a visual AI editor for product designers to make UI changes. Designers ship the changes they make directly to their codebase. The most painful problem for designers today is that their vision doesn't match code. Rivet replaces slow collaboration between designers and engineers by letting designers just do it themselves. Rivet's editor helps turn product designers into design engineers. Design-led companies in YC are Rivet customers. Learn more at rivet.design

Topological is developing physics-based foundation models for CAD optimization. We help hardware teams iterate at the same speed that software teams do. Our technology is accelerating the engineering workflow with AI and scales design and optimization to identify the ideal designs for complex problems given their physical constraints with enhanced speed and performance. Our first model, UToP-v1, is a SOTA topology optimization model that understands physics, geometry, and manufacturability. It can generate the most efficient design given a problem’s physical requirements. It has <5% compliance error and is 1930x faster than current methods. We're reimagining mechanical engineering and computational design with precision spatial AI.

Alkali is building the next generation of estimation tools for construction.

Onlook is the fastest way for anyone to build, deploy, and iterate on websites and web apps. We built an open-source, visual editor for code that merges design, development, and AI. Since launching, Onlook hit #1 on Hacker News, was the #1 trending repo on GitHub—above DeepSeek—and has earned over 8,500 GitHub stars. Founded by Daniel Farrell, a designer of 10+ years and former Head of Growth, and Kiet Ho, an ex-Amazon and ex-ServiceNow engineer, Onlook is on a mission to finally solve the gap between design and development.

Creative intelligence

Ficra enables product teams to ship higher quality releases, faster. Ficra is the source of truth for every product screen and user flow, giving companies real-time visibility into what their users actually see in their live product. Ficra's AI provides a live, visual map of your users’ journeys: every screen, flow, A/B test, push notification and email. With Ficra, product teams no longer waste 25% of their time auditing complex user flows to assess product quality and find the blind spots in funnels.

HeroUI makes it simple for AI agents and developers to build beautiful, accessible, production-ready interfaces for web and mobile. In the AI age, design matters more than ever. Every micro animation, color, and interaction shapes how users experience your product. HeroUI makes that level of creativity and craft simple

ion designs and launches hundreds of on-brand pages for your website, so you close more deals, rank better, and turn your website into a growth engine. Every ad campagin, use case, case study, and competitor comparison gets its own dedicated page, designed to convert. It's like a growth designer working 24/7 to help you convert more traffic.

Midrender is a visual editor for creating motion graphics, powered by AI. Point the agent at your codebase, it reads your code, understands the feature, and creates an animated walkthrough you can ship. A full timeline and design editor lets you fine-tune every detail.

Versive is an all-in-one research platform that helps teams make faster customer-informed decisions. - Collect richer insights: AI-moderated studies that deliver interview-quality results at the survey speeds - Accelerate your analysis: AI-assisted analysis that instantly turns transcripts into shareable insights

Unlayer helps companies add AI-powered content creation into their products without building it from scratch. Developers can embed visual builders for emails, pages, popups, and documents, then connect them to AI agents, templates, asset storage, exports, and APIs. We give teams the building blocks to let users and AI workflows create, edit, personalize, translate, and ship content directly inside their own product.

Mach9 accelerates how teams model and understand the world with automated feature extraction technology. Founded in 2021 and headquartered in San Francisco, Mach9's flagship Digital Surveyor platform helps transportation agencies, utility companies, and engineering firms extract miles of road corridor projects in a fraction of traditional processing time. Built on decades of research from Carnegie Mellon University's Robotics Institute, Mach9 empowers the architecture, engineering, and construction industries to tackle large-scale infrastructure projects with unprecedented speed and accuracy. Leading survey and geospatial organizations, including Langan, Olsson, Woolpert, HDR, and major state DOTs trust Digital Surveyor to create engineering-grade maps for infrastructure design and operations.

Great Question puts customer research on autopilot - from recruiting participants, scheduling interviews, sending surveys or prototype tests - and sharing what you learn with your team. Companies like Adidas Runtastic, O'Reilly Media & MainStreet use us to put their customers at the center of their product, design & marketing decisions.

Manage the words across your team’s product from design to production.

From MIT's App Inventor and YCombinator's W2016 batch, Thunkable allows anyone to build powerful native apps. With Thunkable, it's simple to design, and simple to code-- simply drag and drop to create fast, native, reliable apps. You don't need to download large development suites, command-line kits, or simulators. You can use the many built-in app templates as they are, or make changes. Make your changes online and see them on your device instantly with the Thunkable mobile app. Upload your apps directly to the Play Store or App Store or send them to friends!

Zeplin is an organized workspace to publish finalized designs, where the entire team can collaborate to ship beautiful products together. We were founded in 2014 and today we are honored to support 5+ million users from thousands of product teams including Apple, Starbucks, Salesforce, Amazon, Microsoft, Audi and many more. We’re a Y Combinator startup, also backed by amazing investors like Elad Gil, Mike Maples, Kevin Hale. We’re a distributed crew with offices in San Francisco, Istanbul and London. We're Hiring! Please apply directly on Zeplin's job site: https://zpl.io/jobs

Tumult Inc. makes the next generation of designer tools to produce beautiful web content.

Let AI turn your ideas into a website in minutes. Get content, structure, and style done for you, ready to edit and publish instantly.

Easel was borne out of our frustration with the current state of design tools. Development tools have improved as the web has matured but design tools haven't. We started Easel because we want to create better design tools for the Web. Easel is a member of the Summer 2012 Y-Combinator batch and is located in the San Francisco Bay Area.