Fireworks AI

Fireworks AI runs open-source models like Llama, Mixtral, and Qwen with custom CUDA kernels and batching that noticeably undercut larger cloud providers on both speed and cost. Its FireFunction models are specifically fine-tuned for reliable JSON output and tool-calling, which is what makes it a popular pick for structured extraction and agentic workloads where the output format actually has to be correct, not just plausible.