21st
YC W26San Francisco, US · Founded 2024 · 3 employees · 3 known investors
21st.dev provides a library of thousands of components and templates from the community for developers to use in building applications.
Also known as 1code (21st.dev) · 1code (ex: 21st.dev) · 1code by 21st.dev · 21st.dev
Founders & leadership· Y Combinator alumni (W26)
21st was founded in 2024 by Serafim Korablev and Sergey Bunas.
SK
Serafim Korablevin𝕏Co-founder, CEOSerafim Korablev co-founded 21st.dev, a UI components registry, and previously co-founded Rork.com (a web app builder for Next.js), a Telegram-native memecoin launchpad, and Via, a cross-chain crypto routing protocol. He has been working full-time on product design since October 2023.
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Sergey Bunasin𝕏Co-FounderSergey Bunas is a computer science dropout who previously worked as a Senior Software Engineer at Deel. He built Suggesty, a search product launched in 2022, and Stage, a design tool that reached 10K users before joining his current venture.
Investors · 3
TRAC (Third Round Analytics Capital)San Francisco · $250K – $2Mvia Fred Campbell · inferred
Y CombinatorSan Francisco · $500K
Also in the syndicate · 1
FPV Ventureslead
Funding
SEC filings, press & company announcements- Undisclosed amountSeries AFeb 2026
FPV Ventures (lead)
Source ↗
Source: company announcements and press reports — follow each round's link for the claim.
Images
Competitors · 5
by search overlap
Figma594 shared keywordsFigma is a collaborative design platform that enables teams to create apps, websites, and products through shared design tools integrated with development workflows and AI-powered design assistance.
Webflow359 shared keywordsWebflow is a visual content management system and web design platform that enables creative teams to build, design, and publish brand-forward websites without heavy reliance on developers. The platform serves creative agencies, marketing teams, and enterprises seeking to maintain brand consistency while executing complex web experiences at scale.
LogRocket336 shared keywordsLogRocket provides session replay, product analytics, and AI-powered issue detection for web and mobile applications. The platform helps product teams understand user behavior, identify technical and UX problems, and monitor frontend performance.
Behance296 shared keywordsBehance is a portfolio and community platform for creative professionals to showcase their work, discover clients, and grow their careers. The platform connects creators with potential business opportunities and clients globally.
Stackblitz288 shared keywordsStackBlitz provides a browser-based development environment for creating and launching web applications, with code execution happening entirely within the user's browser using WebAssembly technology. The platform enables developers to write, run, and debug applications without reliance on remote cloud servers.
Companies competing with 21st for the same Google search keywords, organic and paid, via search-intersection analysis.
In the news
New federal housing law could help Berkshire County build more affordable homes | Local News | The Berkshire Eagleberkshireeagle.com · Jul 2026Frequently asked questions
- What does 21st do?
- 21st.dev provides a library of thousands of components and templates from the community for developers to use in building applications.
- Who founded 21st?
- 21st was founded by Serafim Korablev, Sergey Bunas in 2024.
- Who are 21st's investors?
- 21st's investors include TRAC (Third Round Analytics Capital), Y Combinator.
- Where is 21st headquartered?
- 21st is headquartered in San Francisco, US.