Today, we're thrilled to announce $6.2m in new funding led by Martin Casado at Andreessen Horowitz, with continued participation from S28 Capital, Fathom Capital, and South Park Commons. The formal press release is available below.

This funding marks a major milestone for Clerk. For the first time, we've raised based on the traction of our customers, who are simply blowing us away with their continued success. Here's a chart showing cumulative sign ups across all customer applications since we launched:

Our key insight at Clerk is that the Component is the new API. In fact, over 95% of our customers use all of our <SignUp/>, <SignIn/>, and <UserProfile/> components! Of the few who implement our APIs directly, most will build a custom sign-up flow with our APIs, but still use our <SignIn/> and <UserProfile/> components for efficiency.

This outcome is obvious in hindsight. Components combine the power of backend APIs with beautiful, prebuilt frontends, so they inherently deliver more value than APIs alone. We believe component-based integrations have set a new standard for developer tools, and we're excited for the massive improvement in developer productivity they enable.

With this new funding, Clerk will reinforce and expand on our foundation, including:

• Continued, emphatic support for cutting-edge frameworks like Next.js, Remix, Redwood, and more on the way
• Additional authentication strategies like passkeys and SAML SSO
• Expanded capabilities in our <CreateOrganization/> and <OrganizationProfile/> components for B2B SaaS

We can't wait to see what you build!

Press Release

Clerk, the drop-in authentication and user management solution for React, announced today that it has closed a $6.2m seed round led by Andreessen Horowitz. Existing investors S28 Capital, Fathom Capital, and South Park Commons also joined the round. This new funding will allow Clerk to expand its suite of authentication and user management tools, and create new tools to help B2B SaaS companies manage both user accounts and business accounts.

Clerk empowers React developers to build sign-up and sign-in flows as well as user profiles without the assistance of backend developers. The solution comes complete with security essentials like multi-factor authentication and active device management. The beautifully designed React components can be customized to match any company's branding. By providing a full stack solution, Clerk minimizes the time engineers need to spend on authentication, freeing up development resources to focus on the core of their business.

The vast majority of authentication solutions on the market today are still managed in-house and are often incomplete and fail to meet security best practices. Many of these solutions are dated, as web development technologies have evolved to component-based frontend technologies like React. With Clerk’s solution, developers are getting what they prefer—components—because they help them move faster. Components are especially appealing in authentication and user management where businesses do not get much benefit from reinventing the wheel of self-serve 2FA or avatar-uploading. Clerk includes both in their <UserProfile/> component.

"Our key insight is that React Components have replaced REST APIs as the premier developer experience," said Colin Sidoti, Clerk cofounder and CEO. "Since components have a built-in backend and presentation layer, they're an order-of-magnitude faster to implement than APIs."

While Clerk is intended for React frontends, the authentication solution works with any framework, programming language, or API gateway on the backend. This approach has been especially helpful for legacy web applications that are transitioning to React on the frontend, but do not want to change their backend technology.

"There's a growing preference for React among businesses of all sizes, and devtools must evolve to cater to this new architecture. Clerk is hands-down the easiest and most-complete approach to auth and user management in React today," said Martin Casado, General Partner at a16z. "We are excited to help accelerate Clerk's growth and reach more businesses, founders and startups who are looking for easy authentication and user management."

Clerk's vision is to build a truly complete customer management solution for developers, helping facilitate authentication, authorization, communications, billing, and more. Clerk believes these essential services can all be bundled together, and presented cohesively in simple React components.

Notable startups using Clerk include database company Grafbase, women's shapewear company Honeylove, and apartment rental company Blueground. Clerk's React-optimized solution has led the company to be included in Netlify's Jamstack Innovation Fund, and named one of the 10 most promising Jamstack startups.