San Francisco-based Blacksmith has raised $66 million in Series C funding led by Sequoia Capital at a $1 billion valuation, just two months after completing its previous financing round.
Premji Invest participated alongside existing investors Peak XV Partners, GV and Y Combinator. The new financing brings Blacksmith's total funding to approximately $125 million.
Founded in 2024 by Aditya Jayaprakash, Aditya Maru and Aayush Shah, Blacksmith is building cloud infrastructure for continuous integration (CI), the process of automatically building and testing software before code changes are merged or released.
Its rapid growth reflects a shift in software development. AI coding agents can now generate substantial amounts of code with limited human involvement, but that code still needs to be compiled, tested and validated before entering production.
Blacksmith provides computing infrastructure specifically optimized for these workloads. Rather than requiring engineering teams to manage their own CI servers or configure general-purpose cloud infrastructure, the company runs automated tests and builds on its specialized computing platform.
The system integrates with existing developer workflows, particularly GitHub Actions, allowing companies to replace or supplement traditional CI infrastructure without rebuilding their software development processes.
Blacksmith's architecture is designed to handle unusually volatile demand. Software tests can generate large bursts of computing activity when developers submit changes, followed by periods of little activity. According to the company, individual customers can move from almost no usage to requiring tens of thousands of CPUs.
The growth figures illustrate the opportunity.
Since January 2026, Blacksmith says its annual recurring revenue has increased 17-fold. Weekly CI jobs running on its infrastructure have grown from approximately five million to more than 90 million, while its customer base has expanded to over 10,000 companies.
Customers include Mercury, Granola, Handshake and LangChain.
The Series C follows a $45 million Series B announced in August at a $550 million valuation. In September 2025, the company had been valued at approximately $60 million after raising its Series A.
Blacksmith now manages just under 10 megawatts of computing infrastructure across data centers in the United States and Europe. The company plans to increase that footprint approximately fivefold in 2027.
The new capital will also support engineering recruitment and infrastructure expansion.
Blacksmith's growth highlights a second-order effect of AI coding. Producing software is becoming cheaper and faster, but verifying that software works correctly requires additional computation.
The company is betting that software validation will become an increasingly important category of cloud infrastructure as AI agents take responsibility for larger portions of engineering work.
Competition includes established CI providers, cloud infrastructure companies and platforms such as GitHub, which already control important parts of developer workflows.
Blacksmith's challenge will be sustaining its speed and cost advantages while managing the capital intensity of dedicated computing infrastructure. Its reported revenue growth is substantial, but the company has not disclosed absolute ARR, gross margins or profitability.
The longer-term question is whether Blacksmith can establish itself as a default infrastructure layer for AI-driven software development, rather than a faster alternative within an existing CI market.