Production Monitoring for an Increasingly Agentic World: Announcing Raindrop’s Series A

In December 2025, we led Raindrop’s seed round on a simple thesis: as agents become the predominant form of software, observability has to fundamentally change.

The company predicted that traditional evals would give way to production monitoring that surfaces the failures humans — or even traditional monitoring tools — would miss.

Today, we’re proud to double down on that thesis and this team as part of their Series A bringing total funding to $50 million.

Over the past year, demand for production monitoring has only grown, with agents being deployed into industries like defense, healthcare, and financial services. Research from METR shows that the length of tasks frontier AI agents can complete autonomously with 50% reliability has roughly doubled every seven months since 2019. This means that bad behavior is no longer just an inconvenience, but a liability.

Agents don’t fail like traditional software. There’s no stack trace or 500 error. An agent fails by doing the wrong thing convincingly, at scale, until someone happens to notice.

We believe Raindrop was built for this moment: its product reads production agent trajectories and surfaces semantic anomalies like hallucinated answers, tool misuse, or behavior shifts from a model upgrade. Most critically, this often happens before a user notices an issue. It treats agent failure the way a great security company treats intrusion: as a detection problem.

Since its seed round, Raindrop’s product success has largely spoken for itself. Today, Vercel, Clay, and a growing list of large enterprises run Raindrop on their production agent traffic.

The company has also expanded its capabilities to further support its customer base. Simulations, now in research preview, bring the testing process frontier labs use on their own models to every team operating agents. Simulations enable Raindrop customers to replay production traffic against proposed changes to see the impact of planned changes before anything ships. Every platform shift creates a handful of companies that become the infrastructure others build on.

As agents take on real money, health data, and customers, reliability becomes the precondition for deployment. In our view, Raindrop has the customer proof, the technology, and the velocity to own that layer. We’re proud to continue backing their mission.

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