Fireworks AI closed a $1.505 billion Series D at a $17.5 billion valuation, nine months after a $4 billion Series C. The inference startup founded by ex-Meta PyTorch lead Lin Qiao has crossed $1 billion in annualized revenue, a fivefold jump year-over-year, and now processes 40 trillion tokens per day for customers including Cursor, Uber, and DoorDash.