GPT o4-mini
o4-mini is OpenAI's compact reasoning model, released on April 16, 2025 alongside o3. It applies the same chain-of-thought approach at lower cost and latency than the full-size reasoning models, accepts text and image input, and can use tools such as web search and Python while reasoning. OpenAI names the reasoning line without a GPT prefix, so the model is o4-mini, not GPT-o4-mini. It exists so that chain-of-thought reasoning can be used in high-volume workloads where the price and latency of a full-size reasoning model would be prohibitive. Like o3, it runs only on OpenAI's hosted endpoints, not on local or edge hardware. OpenAI has not published the architecture, parameter count or compression techniques behind o4-mini; the documented facts are its context window, pricing, supported input modalities and the benchmark results in the o3 and o4-mini system card. OpenAI reported that it outperforms its predecessor o3-mini on mathematics, coding and visual reasoning benchmarks, and it is priced well below o3 per token. Typical applications are automated analysis, decision support, educational tools and business intelligence, where reasoning quality matters but the budget does not allow a frontier model on every request. It is used through the OpenAI API; in ChatGPT it was offered alongside the higher reasoning-effort variant o4-mini-high until OpenAI retired it from ChatGPT in February 2026.
Related terms
Related services: LLM development, Agentic AI consulting.
Ready to put agentic AI to work?
Book a free 45-minute consultation. We'll map one real process worth automating with production-grade AI.