Blacksmith, a cloud platform used to construct and check software program code, has raised $45 million in a Collection B funding spherical led by Peak XV Companions, valuing the startup at $550 million.

Present investors Y Combinator and GV additionally participated within the financing, which was accomplished in March 2026 and publicly introduced on 12 August.

The spherical takes Blacksmith’s whole funding to $58.5 million, following a $3.5 million seed spherical and a $10 million Collection A.

The startup is searching for to develop as AI coding instruments enable builders to supply software program extra rapidly, growing the quantity of code that should then be examined and reviewed earlier than it may be launched.

Blacksmith mentioned the variety of steady integration, or CI, jobs operating on its platform had elevated by between 5% and 10% every week for the reason that starting of 2026.

CI techniques mechanically construct and check modifications to software program, serving to improvement groups determine issues earlier than new code is merged or launched.

Greater than 6,000 firms now use Blacksmith, together with Supabase, Clerk, Ashby and Mercury. That compares with about 800 organisations when the startup introduced its Collection A funding spherical in September 2025.

It mentioned the rising use of coding brokers comparable to Claude Code and OpenAI’s Codex had resulted in engineering groups producing extra code and opening extra pull requests, creating extra demand for techniques that may validate these modifications.

“Writing code has gotten dramatically simpler. Validating it hasn’t,” mentioned Aditya “JP” Jayaprakash, Blacksmith’s co-founder and CEO.

“We’re seeing groups undertake coding brokers, generate a number of instances extra pull requests, and immediately CI turns into a bottleneck. Each piece of code an agent writes nonetheless must be constructed, examined, and reviewed earlier than it could possibly ship. That validation layer goes to change into more and more vital as extra software program is written by brokers,” he mentioned.

Blacksmith was based in 2024 by Jayaprakash, Aayush Shah and Aditya Maru and was a part of Y Combinator’s Winter 2024 batch.

Its unique product targeted on operating GitHub Actions workloads, which builders use to automate software program builds, assessments and different processes.

Blacksmith operates infrastructure designed particularly for CI workloads, with devoted computing sources in addition to caching and storage techniques meant to hurry up software program testing.

The startup mentioned builders can transfer present GitHub Actions workflows to its platform by making a one-line change to a workflow file.

It additionally mentioned its {hardware} is twice as quick and that its service prices 60% lower than GitHub-hosted runners. These efficiency and pricing figures are based mostly on Blacksmith’s personal comparisons.

The startup has since expanded into AI-assisted software program improvement with Codesmith, a cloud-based coding agent that builders can delegate duties to.

Blacksmith mentioned Codesmith can construct options and repair bugs, whereas additionally working throughout the software program validation course of.

Its Autofix characteristic displays pull requests for failed CI checks and overview suggestions and may try to diagnose an issue, produce a repair and commit the ensuing change.

Blacksmith can be growing Codesmith QA, which the corporate mentioned will autonomously check software program modifications earlier than they’re merged.

Many of the cash raised within the Collection B can be used to extend Blacksmith’s computing capability.

In keeping with the startup, it at present manages a whole lot of 1000’s of computing cores and plans to develop that capability by about tenfold within the coming months as demand will increase.