Fine-tuning on your proprietary data is the highest leverage thing you can do. Prompts get copied overnight. A model trained on your data, y…

Fine-tuning on your proprietary data is the highest leverage thing you can do. Prompts get copied overnight. A model trained on your data, your evals, your edge cases is a strong moat. OpenAI is winding that path down. Don't give up the leverage. Bring the exact same OpenAI SFT JSONL to Fireworks. No conversion. Same messages, tool-calls, per message weight masking etc. Train on GPT-OSS, Kimi, Qwen etc. open weight models you can audit, serve, and own end to end. Your data → your model → your differentiated AI stack. https://developers.openai.com/api/docs/deprecations

Source: Fireworks AI (X) | 2026-05-11