Today, we're excited to announce that Clerk has raised a $15 million Series A led by Madrona, just a few months after our seed. We're especially thrilled that Karan Mehandru has joined our board, who has tremendous experience in our industry from his time on Auth0's board.

More exciting than fundraising, though, is that Clerk is growing – and fast:

Our growth accelerated in the new year as word-of-mouth and referrals became our #1 source of new customers. Here is some of the incredible enthusiasm developers are sharing on X:

We're so grateful for our early adopters who helped hone Clerk into a streamlined solution – and then told their friends! Without them, we simply wouldn't be here today.

Of course, our work is far from done. Throughout the year we'll continue launching new authentication features, like SAML SSO, passkeys, and support for more frameworks.

We're also eager to begin helping developers with authorization. We'll expand customer profiles to include information about Roles and Permissions, as well as Billing and Entitlements. We'll solve authorization through components and hooks, same as we did authentication.

As always, if there's anything in particular you'd like to see from Clerk, or if you have feedback or suggestions, we'd love to hear from you. Join our community discord or tweet at @clerk – we're listening and eager to improve.

Press Release

Clerk raises $15 million for React authentication and user management

Clerk, the drop-in authentication and user management solution for React, today announced a $15 million Series A led by Madrona, with managing director Karan Mehandru joining its board. Mehandru brings a deep understanding of the space from his years on the board of Auth0. Other new investors include Vercel's CEO Guillermo Rauch, Mango Capital, and Auth0's former CRO Dave Wilner. Existing investors Andreessen Horowitz, S28 Capital, and Fathom Capital also participated.

"The response from React and Next.js developers has been incredible. Monthly active users have grown 500% in the past 5 months, and we've crossed a million managed users," said co-founder and CEO, Colin Sidoti. "When we met Karan, we were excited to tap into his experience in identity and in scaling go-to-market as we target the next generation of application development."

React and frameworks like Next.js have sparked an architecture shift that will propagate across all application development, and this new architecture requires a tailored suite of developer tools. Hosting and database technologies have already evolved, but before Clerk, authentication was left to be solved in-house.

“Clerk is the Stripe Checkout of authentication and user management, except it’s built for React," said Rauch, who also authors Next.js. "The best practices built-in to their <SignIn/> and <UserProfile/> components would take months to implement in-house, yet no sacrifice is made in terms of Enterprise extensibility or customization to your brand.”

With this new funding, Clerk will accelerate its roadmap beyond authentication. It aims to help developers with authorization, which requires knowledge of a user's role and permissions, as well as their billing plan and entitlements. Clerk will provide the glue that binds these systems together, while also empowering React developers to build authorization controls for their end-users.

"Clerk is a foundational technology company dedicated entirely to serving the needs of the next generation of application developers as the authentication industry migrates from back-end APIs to front-end componentized modules," said Mehandru. "As this market evolves, Clerk is extremely well positioned to be the "system of action" and the "system of record" for customer identities, much like what Auth0 accomplished in the last decade. I am excited to partner with Colin, his brother and cofounder Braden, and the Clerk team as they empower the developers of the future and build an enduring and exciting company over the next decade and beyond."

Clerk is actively hiring across product and engineering roles. Please visit clerk.com/careers for more information.