OpenAI model releases

OpenAI's mid-2026 flagship, headlined by an industry-leading 1.5M-token context window and long-horizon agentic tool use.

Workhorse GPT-5 release with a dedicated Thinking mode; widely deployed across ChatGPT and the API.

Smaller gpt-oss reasoning model optimized for local inference on systems with about 16GB of memory.

OpenAI's larger open-weight reasoning model, a 117B-total / 5.1B-active MoE with 128K context for local and self-hosted deployment.

Reasoning model released alongside o4-mini with tool use, image reasoning, and stronger agentic problem solving.

API model family focused on coding, instruction following, and one-million-token long-context work.

General release of OpenAI's o1 reasoning model with stronger deliberative reasoning and multimodal ChatGPT integration.

OpenAI's first public reasoning-model preview, optimized to spend more inference time on hard math, coding, and science tasks.

The 2024 omni-modal model that defined a generation of assistants. Deprecated in Feb 2026 and fully retired across ChatGPT on April 3, 2026.

Lower-cost GPT-4 generation with a 128K context window, introduced at OpenAI DevDay.

The model that brought reliable multi-step reasoning to the mainstream; size never disclosed.

OpenAI's first ChatGPT API model, bringing the GPT-3.5 chat-tuned line to developers at much lower cost than text-davinci-003.

The 175B model that proved in-context learning at scale; its base API models were retired in 2024.

Initially withheld over misuse fears, then fully released in Nov 2019 — an early 'limited release' debate.