depthfirst, an applied AI lab dedicated to software security, has closed an $80 million Series B funding round led by Meritech Capital. This investment, coming less than three months after its Series A, elevates the company's total capital to $120 million. The announcement coincides with the launch of its first proprietary security model, dfs-mini1, for securing cryptocurrency smart contracts.
A New Paradigm in AI-Driven Cybersecurity
The rapid integration of AI into software development has created unprecedented challenges for traditional security systems. Attackers now leverage AI to identify vulnerabilities more efficiently, leaving legacy security programs struggling to keep pace. This evolving threat landscape necessitates a shift toward AI-native security solutions that operate at modern development speeds.
According to CEO Qasim Mithani, the industry recognizes that AI will disrupt the established security stack. He emphasized that success requires deploying security-specific models within products tailored for real-world security workflows. This approach addresses the gap left by general-purpose systems that lack the specialized focus needed to counter sophisticated attacks.
The Launch of a Specialized Security Model
In a significant step forward, depthfirst has introduced its first in-house security model, dfs-mini1. This model was developed by post-training an open-source foundation through reinforcement learning in specific security environments. Its initial application is focused on identifying vulnerabilities in cryptocurrency smart contracts, a critical area requiring high precision.
Initial benchmarks show dfs-mini1 outperforming larger models while operating at a fraction of the cost, between 10 to 30 times lower. CTO Andrea Michi noted that owning the training process allows for optimization on key metrics like vulnerability detection. Early evaluations also suggest the model's capabilities can be generalized to other security tasks, demonstrating a versatile approach.
Strong Investor Backing and Market Validation
The $80 million funding round was spearheaded by Meritech Capital, with participation from Forerunner Ventures and The House Fund. Existing investors, including Accel, also reaffirmed their confidence in the company’s vision and rapid execution. This quick succession of funding highlights the significant market demand for advanced, AI-powered security platforms.
Arsham Memarzadeh of Meritech Capital praised depthfirst's rare combination of research capabilities and deep security experience. Sara Ittelson of Accel added that the company's strategy to own both the product and the underlying intelligence is a key differentiator. This full-stack approach is seen as crucial for fundamentally changing how modern software systems are secured.
Since its launch in late 2025, depthfirst has partnered with enterprises and high-growth companies like ClickUp and Supabase. The platform has demonstrated remarkable efficacy, with an impressive 80% of its automated fix recommendations being accepted by developers. This high adoption rate underscores the platform's accuracy and its ability to integrate seamlessly into developer workflows.
Charting the Course for Future Growth
With the new capital, depthfirst plans to accelerate its research and development efforts. The company will focus on training additional specialized security models to cover new and emerging domains beyond smart contracts. A key priority is also expanding its AI research team to continue pushing the boundaries of automated security.
The successful Series B funding and the launch of dfs-mini1 mark a pivotal moment for depthfirst, validating its specialized approach to cybersecurity. As software development becomes increasingly complex, the company is well-positioned to provide the intelligent security solutions needed to protect the digital ecosystem. This strategic capital will fuel its mission to secure the world's software against sophisticated threats.