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o1, o1-pro, o3-mini and o4-mini shut down on 23 October 2026

On 23 October 2026 OpenAI retires its reasoning models o1, o1-pro, o3-mini and o4-mini. It recommends gpt-5.6-sol for o1, o1-pro and o3-mini, and gpt-5.6-terra for o4-mini. The reasoning parameter stays; o1-pro becomes gpt-5.6-sol in «pro mode».

Checked on

o1 OpenAI

Shutdown date: 23 October 2026

Official replacement: gpt-5.6-sol

Price per million tokens (input / output): $15 / $60 → $4 / $20

What changes in your code

  • Change the name in model. reasoning_effort (or reasoning.effort) stays and takes none, low, medium (default), high, xhigh and max: start with the level you used, then try one lower.
  • For o1-pro, o3-pro and gpt-5-pro there’s no separate «pro» model: it’s gpt-5.6-sol with reasoning.mode: "pro", Responses API only.
  • max_tokens doesn’t work with reasoning models: use max_completion_tokens or max_output_tokens. OpenAI suggests reserving about 25,000 tokens for reasoning and output when you start.
  • Tools with reasoning: in the Responses API. In Chat Completions, only with reasoning_effort: "none".

Example code

Python
from openai import OpenAI
client = OpenAI()  # reads OPENAI_API_KEY from the environment

resp = client.responses.create(
    model="gpt-5.6-sol",                  # was: "o1"
    reasoning={"effort": "medium"},  # start with the level you used
    max_output_tokens=25000,        # includes reasoning: leave room
    input="Summarise this text…",
)
print(resp.output_text)
Node.js
import OpenAI from "openai";
const client = new OpenAI(); // reads OPENAI_API_KEY from the environment

const resp = await client.responses.create({
  model: "gpt-5.6-sol",                  // was: "o1"
  reasoning: { effort: "medium" }, // start with the level you used
  max_output_tokens: 25000,        // includes reasoning: leave room
  input: "Summarise this text…",
});
console.log(resp.output_text);

Sources: OpenAI · Deprecations · Using GPT-5.6 · Upgrading to GPT-5.6 · Chat Completions API

o1-pro OpenAI

Shutdown date: 23 October 2026

Official replacement: gpt-5.6-sol — with reasoning.mode: "pro" (Responses API only)

Sources: OpenAI · Deprecations

o3-mini OpenAI

Shutdown date: 23 October 2026

Official replacement: gpt-5.6-sol

Price per million tokens (input / output): $1.10 / $4.40 → $4 / $20

Sources: OpenAI · Deprecations

o4-mini OpenAI

Shutdown date: 23 October 2026

Official replacement: gpt-5.6-terra

Price per million tokens (input / output): $1.10 / $4.40 → $2 / $12

Sources: OpenAI · Deprecations

Also on this page:

ft:o4-mini OpenAI

Shutdown date: 23 October 2026

Official replacement: gpt-5.6-terra

Sources: OpenAI · Deprecations

We’ll email you before your model is switched off

One email 30 days before and another 7 days before the official date, with the replacement and what changes in the code. Free, no account, no marketing.

Which models does your app use?
More models (39)

Using more than one model? Paste your code into the free checker.

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Got a whole repository? Check it at once from the terminal, with nothing to install:

npx -y github:ericc2005t/ai-model-sunset

The code, on GitHub →

Questions

What about o3?
o3 (o3-2025-04-16) and o3-pro shut down later, on 11/12/2026, also with gpt-5.6-sol as the replacement.
Is there a «gpt-5.6-pro» model?
No. In GPT-5.6, pro is a mode: reasoning.mode: "pro" in the Responses API, with any model in the family.
Does the price change?
o3-mini and o4-mini cost $1.10 / $4.40 per million tokens; gpt-5.6-sol costs $4 / $20 and gpt-5.6-terra $2 / $12. o1 cost $15 / $60.

Rather I fix it for you? Model swap, €79; full migration, €290–490. I reply within 24 h with a fixed price.

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