Blacksmith has raised a $66 million Series C led by Sequoia Capital at a $1 billion valuation. The San Francisco company, which runs the infrastructure that software teams use to test their code, announced the round on 21 October 2026. The Blacksmith Series C comes ten weeks after it disclosed a round at $550 million.
What the Round Contains
Sequoia Capital led, and Premji Invest joined as a new backer. Three existing investors returned: Peak XV Partners, GV and Y Combinator. Blacksmith said the money will go towards growing its team and expanding its compute footprint.
Isaiah Boone, a partner at Sequoia Capital, said in Blacksmith’s announcement of the round: “What stood out to us was their deep systems expertise and speed of execution.”
The company puts its total funding at $125 million. Dealroom, which tracks private financing, records roughly $124.5 million; the difference is a rounding of earlier rounds rather than a disputed figure.
Three Valuations in Eighteen Months
The pace of the re-pricing is the most concrete thing about this round, and it is the part most coverage states only in passing.
| Round | Amount | Valuation | Announced |
|---|---|---|---|
| Series A | $10 million | About $60 million | 2025 |
| Series B | $45 million | $550 million | 12 August 2026 |
| Series C | $66 million | $1 billion | 21 October 2026 |
Two details complicate the timeline. The Series B was announced on 12 August 2026 but, by the company’s own account on X, had closed back in March 2026. And the gap between the two announcements is 70 days — ten weeks — over which the stated valuation went from $550 million to $1 billion, an increase of about 82%.
Blacksmith was founded in 2024. Rapid step-ups of this kind are not unique to it: EliseAI doubled its valuation to $4 billion in thirteen months earlier in 2026.
What Blacksmith Actually Sells
Blacksmith sells continuous integration, usually shortened to CI. Continuous integration is the automated step that runs after a developer submits a change: the code is built and its tests are executed, and the change is rejected if anything fails. Every submission triggers a run, so the cost scales with how much code a team writes.
The product is a drop-in replacement for GitHub Actions runners — the machines GitHub rents to customers to execute those runs — hosted on bare-metal hardware, meaning dedicated physical servers rather than shared virtual ones. Blacksmith says customers switch by making a one-line change to a workflow file, after which they no longer provision, scale or maintain the infrastructure themselves.
Which Growth Numbers Are Firm, and Which Are Not
Blacksmith published several growth figures, and they differ in how checkable they are.
- Weekly CI runs: From 5 million in January 2026 to more than 90 million, per the company’s announcement.
- Customers: More than 10,000 companies, per the company. It named Ashby, Granola, Handshake and LangChain. In its August announcement it said more than 6,000.
- Annual recurring revenue: Up 17-fold since the start of 2026. The company gave no absolute figure. Fortune, which reported the round first, put the result in the tens of millions of dollars, a figure the company itself has not published.
- Largest accounts: The biggest customers each spend more than $1 million a year, according to Dealroom’s write-up of the Fortune reporting.
A 17-fold rise from an undisclosed starting point sets no floor on the absolute revenue, which is why the only independent sizing available is a reported range rather than a company number. On that reported range, the $1 billion valuation implies a multiple of roughly 20 to 50 times annual recurring revenue. That arithmetic rests on Fortune’s figure, not on a disclosure. A comparable case on the site: Island’s Series F put $6.4 billion against $200 million of revenue.
The Savings Claim, and What Its Own Customer Said
Blacksmith’s headline performance claim is that CI jobs run twice as fast at 60% lower cost on average. Around the Series B in August, coverage cited a range of 60% to 75% lower cost.
The one named customer quoted in the Series C announcement gave a smaller figure. Joaquin Borggio, an infrastructure engineer at LangChain, said Blacksmith “has significantly reduced the burden of managing our CI runners while cutting our runner costs by roughly 40%”.
Both numbers come from the same press release, so the gap is not a contradiction between sources. A 60% figure is a company-stated average across its base, and 40% is one customer’s own result; averages and individual outcomes differ, and savings will depend on what a team was paying before and how its runs are configured. Blacksmith has not published the methodology behind the average.
Where the Money Goes
Most of the raise is earmarked for computing capacity rather than headcount, which follows from a business that charges for machine time.
- Current capacity: Nearly 10 megawatts across data centres in the United States and Europe.
- Plan: To grow that capacity at least five-fold during 2027.
- Headcount: About 40 staff across San Francisco and New York, with a stated plan to reach roughly 75 by the end of 2026. The company says it is hiring engineers in both cities.
Buying physical capacity with venture money is now a common pattern among infrastructure companies serving AI workloads, as with Mistral AI’s round aimed at compute purchases.
Why Writing Code Faster Created This Market
The demand case rests on a shift in where engineering time is spent. Blacksmith’s position, stated at the Series B, is that CI volume has been growing 5% to 10% every week because code-generation tools make writing code easy and validating it the bottleneck.
The mechanism is straightforward: if an AI assistant helps a team produce more changes, each change still has to be built and tested, so the number of CI runs rises with it. That is the tailwind the company is selling, and the 5 million to 90 million figure is its evidence for it.
What Could Undercut the Business
The structural risk noted in coverage of both rounds is the platform Blacksmith plugs into. Because the product substitutes for GitHub’s own hosted runners, GitHub could bundle faster or cheaper runners as a native feature and remove much of the reason to switch. Blacksmith has not addressed that publicly, and GitHub has announced no such change.
As of 21 October 2026, Blacksmith has raised $125 million in total, holds a $1 billion valuation set by this round, and has published no absolute revenue figure. Private valuations are set by the investors in a round and are not market prices.
Frequently Asked Questions
How Much Did Blacksmith Raise in Its Series C?
$66 million, led by Sequoia Capital, at a $1 billion valuation. The round was announced on 21 October 2026 and brings total funding to $125 million by the company’s count.
Who Invested in the Blacksmith Series C?
Sequoia Capital led the round. Premji Invest came in as a new investor, and existing backers Peak XV Partners, GV and Y Combinator all returned.
What Was Blacksmith Valued at Before?
$550 million, at a $45 million Series B led by Peak XV Partners that was announced on 12 August 2026 and, by the company’s account, closed in March 2026. An earlier Series A of $10 million in 2025 valued it at about $60 million.
What Does Blacksmith Do?
It provides continuous integration infrastructure — the servers that build and test software every time a developer submits a change. It works as a drop-in replacement for GitHub Actions runners, running on dedicated physical hardware.
How Much Revenue Does Blacksmith Have?
The company has not disclosed an absolute figure. It says annual recurring revenue grew 17-fold since the start of 2026, and Fortune reported the result as being in the tens of millions of dollars.
