This was originally posted on the Knock blog.

Three years ago we started Knock to give developers a better way to build notifications.

We had rolled notifications in-house in our past roles and felt the pain:

• Every new feature we shipped meant new notifications to build across each of our frontend clients and out-of-app channels—this took weeks and features often shipped without notification support, leading to poor engagement and retention.
• As our team grew into different squads, the notification system grew disparately across them. Employee turnover meant there was no source of truth and it was impossible to deliver consistent notifications across all features and channels.
• All of our notification logic and templating lived in backend code: our primary engagement engine wasn’t legible to product teams and support teams had to take time from engineering to debug issues.
• Our notification tables scaled faster than the rest of the backend and we had to put down core product priorities to rebuild our notifications infrastructure multiple times.

We left that experience frustrated with the time spent developing and scaling infrastructure that wasn’t our core product. At Knock, we’re building the notification infrastructure platform we wished we had then: easy-to-use API and component primitives for building the notifications you want, without having to scale messaging infrastructure or build in-house tooling to support the rest of your team.

We’re well on our way towards that vision. Knock is used by products like Webflow, Vercel, Amplitude, and hundreds of others to power notifications in production, deliver value to their users, and drive long-term retention.

Today we’re excited to announce a $12M Series A led by Craft Ventures to accelerate growth and redefine customer engagement for products everywhere. David Sacks is joining our board.

Here’s more on what we’re building at Knock, where we’re going from here, and why we’re excited to partner with David and the team at Craft.

Every service that can be abstracted into 3rd-party APIs and components will be

Every successful software product brings a unique value prop to its market. Beneath that value is a layer of critical but generic services—authentication, payments, and notifications.

Each of these services can and should be a 3rd-party API. When this happens, developers get powerful abstractions for services they’d otherwise be maintaining in-house.

That service gets built by a dedicated team with a singular focus. All we think about at Knock is how to scale high-volume, concurrent messaging systems, and how to enable better notification experiences for our customers’ end users.

If you’re a team building notifications in-house, it’s hard to justify the extra time spent on building a batching engine or better preference controls. At Knock, we can always justify that time. Notifications is our core product, and we only have to shlep through a difficult problem once for our entire customer base to get to leverage that solution from that point forward.

The customer gets to use a service that’s better than what they’d build in-house, and the time back to focus on their core product.

The end result: a better experience for end users everywhere.

As we’ve watched the component become the new API, this trend has accelerated. Before teams would look to backend services they could outsource to 3rd-party APIs. Now they look to entire full-stack experiences that they can drop into their app with a component, keep on brand, and outsource to a 3rd-party service.

A great example: Stripe’s evolution from payments API to Stripe checkout.

Building the leading notification infrastructure platform

At Knock we’re building flexible notification infrastructure for every use case. It feels native to your product, and you can run it with the same reliability and observability you’d expect from the rest of your production systems.

The Knock notification infrastructure platform is…

• Our notifications API. Call the Knock API to trigger notifications, schedule cron jobs, manage preferences, and translate messaging for global audiences.
• Our workflow and templating engine. Define notification logic and templating in the Knock dashboard or in code. We provide functions for batching, throttling, and branching to power any use case.
• Our client libraries. Use our pre-built components and SDKs for shipping branded, in-app messaging experiences. Our customers power in-app feeds, task management centers, toasts, and more with Knock.
• Our cross-channel integrations. Frictionless integrations with email, SMS, push, and chat providers (e.g. Slack, Discord, Teams). We handle retries, rate limits, and the other fun details. We also ingest all cross-channel engagement data, clean it, and stream it to your data warehouse and analytics stack.
• Our CLI and developer-first utilities. Work with notifications in code, test and deploy Knock from your CI/CD environment, observe system health from your existing o11y tools.

Why our customers choose Knock

In the less than two years since we officially launched Knock, we’ve brought on more than 200 customers who notify millions of production users every month.

• SaaS vendors like Webflow, Amplitude, and Vidyard use Knock to power user engagement and product announcements.
• Devtools like Vercel, Modal, and FireHydrant use Knock to power threshold billing notifications and to throttle high volume alerts.
• Consumer products like Thingtesting and Bounce use Knock to drive supply and demand activity in their marketplaces.

Across each of these verticals and use cases, these companies are ultimately choosing to use Knock for the same reason: they want to deliver value to their customers in experiences that feel native to their product, and they want to scale that system in a reliable way.

Our $12M Series A from Craft Ventures

We’re excited to partner with David Sacks from Craft Ventures on our Series A. You may know him as the Founder of Yammer, the COO of PayPal, an investor in Slack, Opendoor, and SpaceX, and as Gwyneth’s favorite bestie. We’ve read David’s blog on building and operating SaaS businesses for years, and we’re thrilled to work with him firsthand as we bring Knock to developers and products everywhere.

We’re also stoked to be working closely with Sean Whitney, who first introduced us to the Craft team. Sean led self-service growth at Figma before joining Craft, and in the short time we’ve worked together he’s set a new bar for value add from an investor.

Existing investors participating in this round include our lead seed investor Afore Capital, as well as Expa Ventures, Exponent Capital, Preface Ventures, Tokyo Black, and WorkLife Capital. They’re joined by operators such as Adam Gross (CEO Vimeo), Guillermo Rauch (CEO Vercel), John Kodumal (CTO LaunchDarkly), Michael Grinich (CEO WorkOS), Scott Belsky (CPO Adobe), and Thomas Paul Mann (CEO Raycast).

This brings our total amount raised to $18M, which we’ll use to grow our team, scale our infrastructure, and serve our customers.

Here’s what comes next

Every day at Knock we get to see the impact our product has not just on the developers that use it, but on the users that benefit as a result. Those are users who get fewer, better notifications from the products they use every day.

From here you can expect to see us invest in even better developer-first tooling, more components for building in product notification experiences, and new primitives for expanding the use cases you can address with our workflow engine. All of these mean better notifications for end users.

To all of our customers, we’re grateful you believed in our vision, and that you’ve put your trust in us to help get you there. Thanks for your support and we can’t wait to show you what’s next.

Knock on 🖖

Sam, Chris, and the rest of the team at Knock