Temporal has raised $550 million in a Series E funding round that values the Bellevue, Wash.-based infrastructure startup at $12.55 billion, more than double its valuation from earlier this year as demand explodes for reliable agentic AI systems in production.

The massive round is among the largest venture capital investments in the Pacific Northwest this year and was led by Lightspeed, with co-leads Wellington Management, Growth Equity at Goldman Sachs Alternatives, and Tiger Global.

It caps a significant growth stretch for the open-source platform, whose annualized revenue run rate recently surpassed $250 million — growing over 200% year-over-year, according to a news release on Monday — as major tech players like OpenAI, NVIDIA, Netflix, and JPMorgan Chase rely on its “durable execution” engine to keep complex AI workflows from breaking.

Co-founded in 2019 by CEO Samar Abbas and CTO Maxim Fateev — veterans of Amazon, Microsoft, and Uber — Temporal originally made its mark helping developers manage complex distributed systems.

But as Abbas told GeekWire earlier this year, the AI explosion put that exact problem “on steroids.” While generative AI models handle reasoning, Temporal’s “durable execution” engine acts as the underlying plumbing — preserving application state, retrying failed steps, and preventing multi-step AI agents from crashing when external services drop out.

To support that surge, Temporal has doubled its workforce over the past year to 570 employees worldwide. While operating as a remote-first organization, the company maintains deep roots in the Pacific Northwest — where both founders have been based for decades — and continues to expand its engineering footprint in the Seattle area to keep pace with global demand.

“As agents take on more critical work across more systems, every additional step creates another place to fail. In production, that work has to survive those failures and finish reliably,” Abbas said in a statement. “Temporal was built for this problem. Durable Execution is becoming the standard for reliable applications at scale, and this investment reflects the conviction that much of the next generation of software will be built on Temporal.”

The cash infusion brings Temporal’s total capital raised to date to $1.2 billion, building on a $300 million Series D led by Andreessen Horowitz in February that valued the company at $5 billion.

In addition to Lightspeed, the Series E round drew new backing from Wellington Management, Goldman Sachs Alternatives, and T. Rowe Price, alongside returning venture backers Sequoia Capital, Index Ventures, and Madrona.

Temporal plans to use the fresh capital to accelerate platform R&D, expand its developer and enterprise go-to-market teams, and support global cloud operations.