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https://github.com/jqueryscript/chatgpt-timeline

A timeline of ChatGPT: major events, milestones, controversies, etc.
https://github.com/jqueryscript/chatgpt-timeline

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A timeline of ChatGPT: major events, milestones, controversies, etc.

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# ChatGPT Timeline



A public timeline of major OpenAI GPT model releases, ChatGPT product updates, and related OpenAI milestones.



This repository is built as a clean reference for ChatGPT and GPT release history. It covers GPT-1, GPT-2, GPT-3, ChatGPT, GPT-4, GPT-4o, OpenAI reasoning models, GPT-5, Codex, Sora, ChatGPT Images, GPT-5.5, and GPT-5.6.



> [Claude Timeline](https://github.com/jqueryscript/anthropic-claude-timeline)



Last updated: June 27, 2026



## What This Timeline Covers



- GPT model release dates

- ChatGPT product milestones

- OpenAI reasoning model releases

- Codex and coding-agent updates

- Sora and video generation releases

- ChatGPT Images and image generation updates

- Major OpenAI API and developer platform milestones



## Quick Release Table: Newest First



| Model or Product | Release Date | Key Highlight |

|---|---:|---|

| GPT-5.6 Sol, Terra, and Luna | June 27, 2026 | Limited preview of the GPT-5.6 series, with Sol as the flagship model, Terra for balanced work, and Luna for fast lower-cost work. |

| GPT-5.5 | April 23, 2026 | Frontier model for coding, research, computer use, documents, spreadsheets, and long-running work. |

| ChatGPT Images 2.0 | April 21, 2026 | New ChatGPT image generation experience and model generation. |

| GPT-5.4 mini and nano | March 17, 2026 | Smaller GPT-5.4 models for faster and lower-cost workloads. |

| GPT-5.4 | March 5, 2026 | Frontier model for professional work across reasoning, coding, agents, and tool use. |

| GPT-5.3-Codex-Spark | February 12, 2026 | Ultra-fast research preview model for real-time coding in Codex. |

| GPT-5.3-Codex | February 5, 2026 | Agentic coding model for professional software and computer-based work. |

| GPT-5.2-Codex | December 18, 2025 | Agentic coding model for complex software engineering and defensive cybersecurity. |

| GPT Image 1.5 | December 16, 2025 | Improved ChatGPT Images model with faster generation and stronger editing. |

| GPT-5.2 | December 11, 2025 | Frontier model series for professional knowledge work and long-running agents. |

| GPT-5.1 | November 12, 2025 | ChatGPT update with GPT-5.1 Instant and GPT-5.1 Thinking. |

| Sora 2 | September 30, 2025 | Video and audio generation model with stronger physics, realism, and control. |

| GPT-5 | August 7, 2025 | Unified GPT-5 system for ChatGPT and developers. |

| Codex | May 16, 2025 | Cloud-based software engineering agent. |

| OpenAI o3 and o4-mini | April 16, 2025 | Reasoning models with tool use across ChatGPT. |

| GPT-4.1 | April 14, 2025 | API model series for coding, instruction following, and long context. |

| 4o image generation | March 25, 2025 | Native image generation in GPT-4o and ChatGPT. |

| GPT-4.5 | February 27, 2025 | Research preview of a larger GPT model for chat. |

| OpenAI o3-mini | January 31, 2025 | Cost-efficient reasoning model for STEM, coding, and math. |

| OpenAI o1-preview | September 12, 2024 | First public reasoning model series from OpenAI. |

| ChatGPT search | October 31, 2024 | Web search experience inside ChatGPT. |

| Canvas | October 3, 2024 | Separate workspace for writing and coding with ChatGPT. |

| GPT-4o | May 13, 2024 | Omni model for text, audio, vision, and real-time interaction. |

| ChatGPT plugins | March 23, 2023 | Early tool system for ChatGPT, later deprecated. |

| GPT-4 | March 14, 2023 | Large multimodal model with text and image input. |

| ChatGPT Plus | February 1, 2023 | Paid ChatGPT subscription plan. |

| ChatGPT | November 30, 2022 | Public research preview of ChatGPT. |

| GPT-3 | May 28, 2020 | 175B-parameter language model for few-shot learning. |

| GPT-2 | February 14, 2019 | Large unsupervised language model and staged release milestone. |

| GPT-1 | June 11, 2018 | Early generative pre-training system for language understanding. |



## Full Timeline



| Date | Milestone |

|---:|---|

| June 2018 | OpenAI published the first GPT research system through work on generative pre-training for language understanding. |

| February 2019 | GPT-2 was introduced as a larger unsupervised language model. OpenAI used a staged release process because of misuse concerns. |

| May 2020 | GPT-3 was introduced as a 175B-parameter language model that showed strong few-shot learning. |

| November 30, 2022 | ChatGPT launched as a public research preview. |

| February 1, 2023 | ChatGPT Plus launched as a paid subscription plan. |

| March 14, 2023 | GPT-4 launched as a multimodal model with text and image input. |

| March 23, 2023 | ChatGPT plugins launched as an early way for ChatGPT to use tools and external services. |

| July 2023 | GPT-4 API access became generally available to paying API customers. |

| May 13, 2024 | GPT-4o launched as a faster omni model for text, audio, vision, and real-time interaction. |

| September 12, 2024 | OpenAI introduced o1-preview, the first model in its reasoning series. |

| October 3, 2024 | Canvas launched as a separate workspace for writing and coding with ChatGPT. |

| October 31, 2024 | ChatGPT search launched for web answers with source links. |

| January 31, 2025 | OpenAI o3-mini launched as a smaller reasoning model for STEM, math, and coding. |

| February 27, 2025 | GPT-4.5 launched as a research preview of a larger GPT model for chat. |

| March 25, 2025 | OpenAI introduced native image generation in GPT-4o. |

| April 14, 2025 | GPT-4.1, GPT-4.1 mini, and GPT-4.1 nano launched in the API. |

| April 16, 2025 | OpenAI o3 and o4-mini launched as reasoning models with access to ChatGPT tools. |

| May 16, 2025 | Codex launched as OpenAI's cloud-based software engineering agent. |

| August 7, 2025 | GPT-5 launched as a unified system in ChatGPT and the API. |

| September 30, 2025 | Sora 2 launched as a video and audio generation model. |

| November 12, 2025 | GPT-5.1 launched in ChatGPT as GPT-5.1 Instant and GPT-5.1 Thinking. |

| November 13, 2025 | GPT-5.1 became available for developers in the API. |

| December 11, 2025 | GPT-5.2 launched for professional knowledge work and long-running agents. |

| December 16, 2025 | GPT Image 1.5 launched through the new ChatGPT Images experience. |

| December 18, 2025 | GPT-5.2-Codex launched for agentic coding and cybersecurity-related software work. |

| February 5, 2026 | GPT-5.3-Codex launched for long-running coding, research, and computer-based work. |

| February 12, 2026 | GPT-5.3-Codex-Spark launched as an ultra-fast research preview for real-time coding. |

| March 5, 2026 | GPT-5.4 launched in ChatGPT, the API, and Codex for professional work. |

| March 17, 2026 | GPT-5.4 mini and GPT-5.4 nano launched for faster and lower-cost use cases. |

| April 21, 2026 | ChatGPT Images 2.0 launched as a new image generation experience. |

| April 23, 2026 | GPT-5.5 launched for advanced coding, research, computer use, knowledge work, and agentic workflows. |

| April 24, 2026 | GPT-5.5 and GPT-5.5 Pro became available in the API. |

| June 27, 2026 | OpenAI began a limited preview of the GPT-5.6 series: Sol, its flagship model; Terra, a balanced model for everyday work; and Luna, a fast and affordable model. Initial access is through the API and Codex for selected trusted partners. |



## Latest OpenAI Model



The latest major GPT model in this timeline is GPT-5.6 Sol, introduced in limited preview on June 27, 2026.



GPT-5.6 Sol is OpenAI's strongest model in the announcement. The GPT-5.6 series also includes Terra for balanced everyday work, with competitive performance to GPT-5.5 at half the cost, and Luna as the fast, lowest-cost model in the series. During the preview, GPT-5.6 models are available through the API and Codex to selected trusted partners, with broader ChatGPT, Codex, and API availability planned soon. OpenAI says the short-term limited preview follows engagement with the U.S. government.



GPT-5.6 adds max reasoning effort for Sol and an ultra mode that can use subagents for complex work. OpenAI cites improved agentic capabilities in coding, biology, and cybersecurity, including Terminal-Bench 2.1, GeneBench v1, ExploitBench, and ExploitGym results. OpenAI says Sol did not cross the Cyber Critical threshold in the reported tests and that it used more than 700,000 A100-equivalent GPU hours for automated red teaming.



API pricing is listed per 1 million tokens: Sol at $5 input and $30 output, Terra at $2.50 input and $15 output, and Luna at $1 input and $6 output. GPT-5.6 also adds explicit cache breakpoints, a 30-minute minimum cache life, cache writes billed at 1.25x the uncached input rate, and a 90% cached-input discount for cache reads. OpenAI also plans to launch GPT-5.6 Sol on Cerebras at up to 750 tokens per second in July for selected customers.



## Source Article



This repository is maintained as a companion resource for the full article:



[ChatGPT Timeline: GPT Release Dates From GPT-1 to GPT-5.6](https://www.scriptbyai.com/timeline-of-chatgpt/)



The article includes a readable web version of the timeline, more context on GPT model generations, and related AI resources.



## Related Resources



- [Anthropic Claude Timeline](https://www.scriptbyai.com/anthropic-claude-timeline/)

- [AI LLM API Pricing](https://www.scriptbyai.com/gpt-gemini-claude-pricing/)

- [ChatGPT Resources](https://www.scriptbyai.com/chatgpt/)



## Disclaimer



This repository is an independent timeline resource. It is not affiliated with OpenAI.



## License



This repository is available under the MIT License.