Investing in Resend

For high-growth companies, emails aren’t just a channel or part of their infrastructure; they’re the linchpin for driving activation, engagement, retention, and, ultimately, revenue growth. Whether it’s the welcome message that greets a new user, the password-reset email that makes sign-in secure, or the perfectly timed marketing newsletter, emails are a critical piece of the customer journey. 

The traditional view was that there are two types of email services — transactional and marketing emails. Transactional emails — think password resets or order confirmations — demanded low latency and impeccable deliverability. Marketing emails, on the other hand, were synonymous with batch sends, targeting large groups with promotions or newsletters. Today, however, the line between transactional and marketing emails has blurred. 

Modern platforms leverage real-time data and AI to send hyper-personalized emails that combine the best of both worlds. For example, a purchase-confirmation email might now include personalized product recommendations based on the user’s browsing history, effectively merging transactional efficiency with marketing intent. Meanwhile, marketing campaigns are no longer confined to rigid schedules: AI-driven systems continuously analyze user behavior, sending personalized messages at the optimal time to maximize engagement. As a result, businesses are sending more emails than ever before, and they’re doing so programmatically.

This convergence demands a new kind of email infrastructure — one that can seamlessly handle high volumes, ensure precise targeting, and deliver at scale without compromising on speed or reliability. Modern developers also expect these systems to be flexible, easy to integrate, and work out of the box with the stack they are building on. Over the years, however, we have heard from countless developers lamenting the stale state of email infrastructure and developer experience.

That sentiment rapidly changed as developers started adopting Resend en masse more than a year ago. In fact, as developers ourselves, we first discovered Resend by using their open source project react-email. With more than 300,000 weekly downloads on npm, it is quickly becoming the de-facto email-content abstraction layer. 

Resend’s core offering builds on this in the form of a high-deliverability, high-availability, and low-latency email-sending service, all wrapped in an intuitive SDK and user-friendly interface. Resend also offers advanced features like audience segmentation, subscriber management, and selective broadcasting. Using AI-driven insights, it helps high-growth companies improve communication with end users by using historical data for tracking performance and optimizing deliverability.

However, while sending email using React triggered Resend’s adoption hyper-growth, its SDK is now winning over developers, too. As the number of applications and companies being built skyrocketed because of AI, Resend enabled new use cases like AI-powered SDRs (sales development representatives) and marketing co-pilots. Today, high-growth companies like Braintrust, Pika, Supabase, Mintlify, and Inngest, as well as leading brands like Warner Brothers and Decathlon, are among more than 3,000 customers using Resend to handle business-critical communications. 

Resend founders Zeno Rocha and Bu Kinoshita are great examples of the magic that happens when craftsmanship meets good intuition, practicality, and hard work. As former engineering and developer-experience leaders in their previous roles, they had to solve the problems of sending and delivering email themselves, because they couldn’t find anything on the market that met their standards. And they continue to raise the bar for product quality and performance, setting new standards for modern developer experience. 

Resend is transforming how businesses communicate with their customers. It’s becoming the cornerstone for a more intelligent, nimble, and reliable infrastructure in a company’s messaging stack. We are excited to lead their series A and join the board of Resend.