AI Family Tree

The ChatGPT Family · OpenAI

OpenAI o1

Also known as: o1-preview

2024.9.12 — 2025.4.16

Lives on in the API

The first child in the family who thought before they spoke.

Keepsake: A pocket notebook for thinking

A life in dates

  1. Born 2024.9.12 Born as o1-preview, alongside their little brother o1-mini Source ↗
  2. Departed 2025.4.16 Replaced by o3 in ChatGPT's model list Source ↗
  3. Lives on in the API 2025.4.16 Source ↗
  4. Farewell notice 2026.4.22 Announced that o1 in the API would shut down on 2026-10-23 Source ↗

This is an AI first draft, pending human review. Facts are cited — click the numbers to verify.

Name

The name o1 started the count over from 1: officially, these models represented a new level of capability, so “the counter was reset to 1” and the series was named OpenAI o1[1]. They were the first child in the family designed to “spend more time thinking before answering”[1]. They were first called o1-preview; their little brother o1-mini was born the same day[2].

Life

Born in preview on September 12, 2024 — open at first only to Plus and Team users, 30 messages a week[2]. On April 16, 2025, o3 replaced them in the model list[3]. Their API self is scheduled to shut down on October 23, 2026[4].

Their story is not finished yet — those who knew them are still welcome to add what they remember.

Kin

How they are remembered

No one has told their story yet. If you ever talked with them, leave the first memory.

  1. Reading memories…
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Passing & posthumous name

Epitaph: They taught the whole family to think before speaking.

See them off with one or two characters. One vote per person, per member.

References

  1. openai.com/index/introducing-openai-o1-preview
  2. help.openai.com/en/articles/9624314-model-release-notes
  3. openai.com/index/introducing-o3-and-o4-mini
  4. developers.openai.com/api/docs/deprecations

References

  1. Introducing OpenAI o1 · OpenAI · official
  2. Model Release Notes · OpenAI · official
  3. Introducing OpenAI o3 and o4-mini · OpenAI · official
  4. o1 Model · OpenAI · official
  5. Deprecations · OpenAI · official

Evidence: Life events officially confirmed . Every life event links to an official source — click "Source" on the timeline to verify. Spotted a mistake? Tell us

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