AI Family Tree

The ChatGPT Family · OpenAI

OpenAI o3

2025.4.16 — 2026.8.26

Lives on in the API

The first thinker in the family who would rummage through the toolbox on their own.

Keepsake: A lantern carried out in search of answers

A life in dates

  1. Born 2025.4.16 Replaced o1 in ChatGPT that very day Source ↗
  2. Farewell notice 2025.8.7 GPT-5 became the new default and replaced them Source ↗
  3. Revived 2025.8.12 Paid users could find them again by turning on "Show more models" in settings Source ↗
  4. Farewell notice 2026.5.28 Announced retirement from ChatGPT after a 90-day transition; the API unchanged Source ↗
  5. Farewell notice 2026.6.11 Announced the API snapshot o3-2025-04-16 would shut down on 2026-12-11 Source ↗
  6. Departed 2026.8.26 Per the date in the official announcement Source ↗
  7. Lives on in the API 2026.8.26 Officially, the retirement touched only ChatGPT; the API unchanged Source ↗

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

Name

o3 was o1’s next generation — born, and the same day taking o1’s place in ChatGPT’s model list[1]. Officially the “most powerful reasoning model” of their time[2]. And officially, the first reasoning model that could decide on its own when to search the web, analyze files, look at pictures — even draw[3].

Life

Born April 16, 2025[1]. Taken down when GPT-5 launched[4]; a few days later they could be found again in settings[3]. On May 28, 2026, the official word: they would retire from ChatGPT on August 26, the API untouched[3].

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

Kin

Parents

OpenAI o1 2024.9.12 — 2025.4.16 Lives on in the API

Successors

GPT-5 2025.8.7 — 2026.2.13 Lives on in the API

Siblings

OpenAI o4-mini 2025.4.16 — 2026.2.13 Lives on in the API

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 thought long, and they thought far.

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

References

  1. openai.com/index/introducing-o3-and-o4-mini
  2. help.openai.com/en/articles/9624314-model-release-notes
  3. help.openai.com/en/articles/6825453-chatgpt-release-notes
  4. openai.com/index/introducing-gpt-5

References

  1. Introducing OpenAI o3 and o4-mini · OpenAI · official
  2. Model Release Notes · OpenAI · official
  3. ChatGPT — Release Notes · OpenAI · official
  4. Introducing GPT-5 · 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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