A San Francisco, CA-based provider Clerk raised $15M in Series A funding led by Madrona for React authentication and user management

Mar 22, 2023

MARCH 22,2023/--Clerk, a San Francisco, CA-based provider of a drop-in authentication and user management solution for React, raised $15M in Series A funding.

The round was led by Madrona, whose managing director Karan Mehandru joined the 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."

About Clerk

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

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

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

It's also eager to begin helping developers with authorization. It will expand customer profiles to include information about Roles and Permissions, as well as Billing and Entitlements. It will solve authorization through components and hooks, same as it did authentication.