Partnering with Blacksmith

Software development has a new bottleneck. Writing code is no longer the hard part; trusting it is. Coding agents now produce more code than any team can read or any existing system can verify. Led by co-founders Aditya Jayaprakash (JP), Aayush Shah and Aditya Maru, Blacksmith is building infrastructure that can. Last month, Anthropic’s engineering team described what happened as their own usage of coding agents scaled. Engineers began shipping roughly eight times as much code per quarter. Their test suite grew tenfold. The volume of continuous integration (CI) jobs, the builds and tests that check every change before it reaches production, grew 25x in six months. Anthropic is very far along the curve, but is on the same curve as every company, and its advice to the rest of the industry was to plan for 25x the CI load within two quarters. For decades, software development scaled as a function of engineering capacity. Developers were the scarce resource. Shipping more meant hiring more. That has changed. Developers now direct fleets of coding agents that work in parallel, around the clock and increasingly autonomously. These agents do not produce finished work. They produce attempts—a patch, a test, a migration, a throwaway branch—each iterating against a test suite until it is ready to merge. Meanwhile, the quiet backbone of software development that validates and tests code has not changed. Validating code has also never been more important. AI coding tasks produce large volumes of security flaws, and the same model capabilities that write the code now make those flaws more dangerous. The system that was supposed to catch them is straining right as developers need it the most. With the scale and velocity of this shift, the constraint in software has moved from writing code to proving it works and is safe. This is the problem Blacksmith set out to solve. The team started with speeding up CI. With a one-line change in a workflow file, developers using Blacksmith see their CI jobs complete twice as fast and at 60% lower cost on average. Underneath a simple product experience is a stack purpose-built from the bare metal up, designed to absorb demand spikes from customers and get faster and more efficient as it scales. Developers have noticed. The business has seen explosive growth this year. More than 10,000 companies are using Blacksmith, up from 700 a year ago. Weekly CI jobs are up 18x, from 5 million to 90 million, in 2026 alone. And ARR has grown 17x over the same time period, with the largest customers now spending more than $1M per year. Much of our conviction in Blacksmith is driven by the team behind it. Co-founders JP, Aayush and Maru have known each other since their undergraduate years at the University of Waterloo, and developed a maniacal focus on hyper-performant systems at Cockroach Labs and Faire. They founded Blacksmith in 2024, as autocomplete was giving way to coding assistants, on the conviction that the volume of code needing to be tested would go up by orders of magnitude. For the rest of the world, the future became clear in 2026 with the arrival of truly autonomous coding agents, but Blacksmith had already been building for it. The Blacksmith team is talent-dense and is growing quickly. The roadmap is exciting, with several launches planned in the coming months. We are proud to lead Blacksmith’s Series C. The world is about to run far more code than it has ever written, and someone has to make sure it works. We look forward to supporting JP, Aayush and Maru as they build infrastructure that runs at agent speed, in validation and beyond.