Fireworks makes its Training API generally available with named customer deltas: Harvey 19.7% vs 10.8%, Vercel v0 93% error-free at 40x lower latency

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Fireworks announced GA of its Training API and Fireworks Lab on Aug 31, exposing SFT, DPO, reward finetuning and RL across three surfaces. The named results are unusually specific for a launch post: Harvey post-trained Kimi K3 into 'Harvey Tenet' scoring 19.7% all-pass on LAB against 10.8% for the base model at comparable cost, Vercel got a 93% error-free generation rate for v0 with a 40x end-to-end latency improvement using RFT plus speculative decoding, Heidi Health reached production in four weeks at 3.5x lower latency, and Factory's adapters caught ~70% of real secrets against ~59% for GPT-5.5 at a 5% false-alarm budget.