Today we're announcing that Guardrail is joining Rain.
Four years ago, we set out to solve a hard problem in blockchain security: how to defend live systems beyond code audits and static runbooks. Our mission remains the same, and we’re excited to deepen our relationship with Rain from customer to buyer, together pooling our resources to build frontier security for stablecoins.
Zero to One
Security remains a foundational challenge for onchain finance. Retail users, investors, and institutions have only multiplied the trust, regulatory, and privacy requirements for live systems. Simply put, developers needed defensive systems to match the blockchain's scale and complexity.
We built Guardrail because (1) only a handful of security experts existed with this experience, (2) blockchains were excluded from all state-of-the-art security tooling, and (3) open-source and open-ledger technology was a level playing field, serving the attackers more than the defenders. When we started, our early customers relied on manual and static security code audits, often months behind ongoing attack patterns, and were missed entirely by audits.
We took a different approach.
At Guardrail, our team of experts broke down the problem into layers: Data layer, Security Layer, Response Layer, mapping each phase of the security lifecycle to build a self-learning system that gets smarter with every block added to the blockchain. Building the system entirely in-house and iterating daily, we’re proud of what we built: the leading security platform that in real-time detects and mitigates risks for exchanges, stablecoins, yield products, and more with millisecond response time and accuracy.
Since going live, we’ve saved our customers combined 9-figures in loss mitigation, our team of 8 protecting over $30 billion in onchain assets across 30+ chains. The highlight: we’ve had the opportunity to work with teams innovating on applications we couldn’t even have imagined, and we’ve been security partners, from day-one launches to IPOs.
Our next chapter: from breadth to depth
We built Guardrail to be modular from the start, so it could defend many kinds of onchain applications, from DeFi protocols to bridges to custodial infrastructure. Working that broadly gave us a clear read on where production-grade security demand was concentrating, and one vertical pulled ahead: stablecoins.
Stablecoins carry real-world money at enterprise scale, and they set a higher bar than general DeFi. The threat surface is different, the throughput is higher, and the standard for detection and response is the one traditional finance holds live financial systems to. The more we worked across stablecoin infrastructure, the more conviction we built in evolving Guardrail from a parallel 24x7 system to an integrated in-line security system.
Why Rain
We've seen in recent history many cases where security is not prioritized early in development, and by the time it is, it's too late. Guardrail has been a security partner with Rain since the early days, from design partners on the security architecture to customers of real-time monitoring across 15+ networks.
"The product is exceptional, but the team is the real reason this matters," Rain Co-founder Charles Yoo-Naut said. "You can't put together this kind of expertise through individual hires. Samridh has assembled one of the very few groups in the world operating at that depth, and we're fortunate to have them at Rain." Combining talent and a security blueprint with Rain's scale and product is a unique match.
This shift from vendor to in-house allows Rain to move through the security lifecycle faster across all its products, closing the gap between detection and remediation. Integrating Guardrail throughout Rain's full transaction flow also gives our models unique context that no outside vendor can accumulate, powering faster and more accurate decisions. Just as teams rush to embed AI to improve products, Guardrail is adapting to AI adversaries targeting each layer of the stack, which is even more crucial for Rain's global stablecoin payments platform.
From our team
None of this would have been possible without the people who built Guardrail into what it is.
Thank you to our early investors and backers: Haun Ventures, Coinbase Ventures, Volt Capital, Canonical Crypto, Alliance, and the partners who backed this work early.
Thank you to our customers who trusted us with keeping your users and funds safe while you built your businesses. We’re honored that we protected each and every one of you.
Special thanks to Guardrail’s team (past and present), every engineer, operator, and designer who built alongside us. We’re back to work on our mission, with a bigger target and team.
We're excited for what comes next. Read more about Rain’s perspective in their blog post: Behind the buy: securing Rain’s onchain stack with Guardrail.
