How Clerk powers their authentication webhooks with Svix

Clerk is authentication as a service. They manage users and sessions with deep integrations into their customers' applications, enabling developers to add complete authentication systems to their apps in minutes rather than weeks.

Clerk serves everyone from new startups to large enterprises, with a particular strength in helping developers who need a login page get up and running quickly. Their platform is used by engineers across the stack, though non-engineers also frequently access the dashboard to view user data, analytics, and leverage features like user impersonation for customer support.

Clerk has been using Svix for over three years, relying on it to power the webhooks that are essential to their authentication platform.

The highest praise you can give any piece of technology is: it just works. Svix lives up to that. It just works, and that's what it's supposed to do.

Webhooks were table-stakes for authentication

When Clerk was a small team of six or seven people, they knew their customers needed webhooks. As an authentication service, Clerk manages critical user data, and customers need a way to keep that data in sync with their own systems.

Braden Sidoti, Clerk's co-founder & CTO, explained that the need was obvious: "The Clerk product was pretty much dead in the water for anyone but the smallest customers if we didn't have that capability."

Webhooks enable Clerk's customers to:

• Sync user data back to their own databases
• Track changes to user profiles and email addresses
• Extend Clerk's capabilities with custom workflows

For a certain segment of customers, Svix makes the product go from not usable to usable. It would be impossible to use Clerk without webhook functionality of some sort.

Build vs. buy: a classic decision

When Clerk first considered implementing webhooks, they faced the classic build versus buy decision. They roughly knew how challenging it would be to implement webhooks themselves, and with only a year and a half of runway at the time, every month mattered.

Braden estimated that building their own solution would have taken at least a month initially, "and it would probably have been really brittle, and we would still be dealing with issues from it today."

A full-featured, reliable implementation with all the necessary functionality would have required at least six months with a skilled team, including someone with deep webhooks expertise. And even then, it would be a continuous maintenance burden rather than a one-time project.

Reliability is key. If we had webhooks but they weren't reliable, then it would be basically just as good as not having them.

Svix: Set it and forget it

Clerk tried Svix early on, before they had any webhook functionality in place. "It just worked, and so that was the decision point," Braden explained.

The initial integration took under two weeks, and over time as they've added more webhook types and changed the data structure, the UI has continued to update seamlessly and provide their customers with everything they need.

When asked what he liked most about Svix, Braden emphasized the low-maintenance nature: "I think the less it sticks out, the better for this particular feature."

He continued: "It's like this isolated little machine that's reliable and works in the background. The few times I've had a question or an issue over the past three years, I've jumped in Slack and you always come up with an answer really quickly."

Performance and scale: It just works

As Clerk has grown significantly over the past three years, Svix has scaled alongside them without any noteworthy performance issues. The integration has been so reliable that it rarely requires attention.

"It just scaled automatically in the background," Braden noted. "We send you more events, and you send more webhooks. We haven't had to think about it at all as we scaled our usage."

It's one of the most well-made installs of any of the products we're using. I don't have to think about it—it's something I don't have to worry about.

The end result

With Svix, Clerk has been able to offer enterprise-grade webhook functionality from day one without the engineering investment or ongoing maintenance burden of building it themselves. This has allowed them to focus on their core authentication product while still providing the critical integration capabilities their customers require.

The partnership has proven its value over three years of consistent, reliable performance. As Braden put it: "It just works, and that's kind of what it's supposed to do."

For developers building authentication into their applications, Clerk offers a seamless experience. And for Clerk's team, Svix offers that same seamless experience for webhooks—allowing them to deliver critical functionality while staying focused on what they do best.