# GPT-4o API Shutdown: January 14, 2027, Move to Luna

> OpenAI retires GPT-4o, GPT-4o mini, GPT-4.1 and GPT-4.1 mini from the API on Jan 14, 2027. The replacement, GPT-6 Luna, prices and notice period.

- Author: Nitish Garg, Founder & CEO, CellCog
- Published: 2026-10-14
- Canonical (HTML): https://cellcog.ai/blog/gpt-4o-api-shutdown/
- Section: Guides / Choosing a platform
- Publisher: CellCog (https://cellcog.ai), the AI employee platform. Blog index for agents: https://cellcog.ai/blog/llms.txt

## Key points

- OpenAI notified developers on October 14, 2026 that four GPT-4 series models leave the API on January 14, 2027.
- The four: GPT-4o (two snapshots), GPT-4o mini, GPT-4.1 and GPT-4.1 mini; fine-tuned versions follow the same schedule.
- OpenAI names one replacement for all four: gpt-6-luna.
- On OpenAI's model pages, GPT-6 Luna lists $0.10 input and $0.50 output per million tokens, against $2.50 and $10 for GPT-4o.
- The notice runs three months; OpenAI's own policy promises generally available models at least six, with an exception for safety or compliance.

## At a glance

- **When does GPT-4o stop working in the API?** January 14, 2027, for gpt-4o-2024-08-06 and gpt-4o-2024-11-20, per OpenAI's deprecations page.
- **What should I migrate to?** OpenAI names gpt-6-luna as the replacement for GPT-4o, GPT-4o mini, GPT-4.1 and GPT-4.1 mini.
- **Is this about ChatGPT?** No. The October 14 notice covers the API; the deprecations page does not mention ChatGPT.

**OpenAI is retiring GPT-4o from its API on January 14, 2027.** On October 14, 2026, it notified developers that GPT-4o, GPT-4o mini, GPT-4.1 and GPT-4.1 mini are deprecated, per its [deprecations page](https://developers.openai.com/api/docs/deprecations). The named replacement for all four is GPT-6 Luna.

If an app or pipeline still calls one of these models, it has three months to move. Here is what changes, what the replacement costs, and what to check first.

## What OpenAI announced

The notice is short: "On October 14, 2026, we notified developers using certain GPT-4 series models of their deprecation and removal from the API on January 14, 2027."

*Table: The October 14 deprecation (OpenAI deprecations page, read October 14, 2026)*

| Model | Snapshots | Shutdown | Replacement |
|---|---|---|---|
| GPT-4o | gpt-4o-2024-08-06, gpt-4o-2024-11-20 | January 14, 2027 | gpt-6-luna |
| GPT-4o mini | gpt-4o-mini-2024-07-18 | January 14, 2027 | gpt-6-luna |
| GPT-4.1 | gpt-4.1-2025-04-14 | January 14, 2027 | gpt-6-luna |
| GPT-4.1 mini | gpt-4.1-mini-2025-04-14 | January 14, 2027 | gpt-6-luna |

One line matters most for teams that trained their own versions: "Fine-tuned versions of these models follow the same shutdown schedule as their underlying base models." A fine-tune on GPT-4o stops on the same day as GPT-4o.

## The notice is shorter than OpenAI's usual

OpenAI's own policy, on the same page, sets the notice it aims to give: at least six months for generally available models. This notice runs three months, from October 14 to January 14.

The page gives no reason. The policy does carry an exception: "If safety or compliance concerns require us to retire a model sooner, we will provide as much notice as reasonably possible." We could not find a statement from OpenAI tying this notice to that clause, so we read it only as a shorter window than the policy's default.

For teams that cannot move in time, OpenAI says "In some cases, developers may be able to provision dedicated capacity for continued access after a model's shutdown date," through its sales team.

## What the replacement costs

On price, the move goes in the developer's favor. These are the list prices on OpenAI's model pages for [GPT-6 Luna](https://developers.openai.com/api/docs/models/gpt-6-luna), [GPT-4o](https://developers.openai.com/api/docs/models/gpt-4o) and [GPT-4.1](https://developers.openai.com/api/docs/models/gpt-4.1), per million tokens.

*Table: Price and limits per model (OpenAI model pages, read October 14, 2026)*

| Model | Input | Cached input | Output | Context window | Max output |
|---|---|---|---|---|---|
| GPT-4o | $2.50 | $1.25 | $10.00 | 128,000 | 16,384 |
| GPT-4o mini | $0.15 | $0.075 | $0.60 | 128,000 | 16,384 |
| GPT-4.1 | $2.00 | $0.50 | $8.00 | 1,047,576 | 32,768 |
| GPT-4.1 mini | $0.40 | $0.10 | $1.60 | 1,047,576 | 32,768 |
| GPT-6 Luna | $0.10 | $0.01 | $0.50 | 1,050,000 | 128,000 |

At list price, GPT-6 Luna's input is 25 times cheaper than GPT-4o's and its output 20 times cheaper. Against GPT-4o mini, the cheapest of the four, Luna is 1.5 times cheaper on input and 1.2 times on output. Luna's context window is about eight times GPT-4o's, and its maximum output is nearly eight times larger. Its knowledge cutoff is May 18, 2026, against October 1, 2023 for GPT-4o.

## What to test before you switch

A cheaper, newer model is not automatically the same model. Before January:

- **Run your own prompts.** Output style, length and formatting can change between model families. Compare a sample of real requests side by side.
- **Check structured outputs.** If your code parses JSON or tool calls, confirm the parse rate holds.
- **Watch latency.** A different model can answer faster or slower; measure it on your traffic.
- **Rebuild fine-tunes early.** If you depend on a fine-tuned GPT-4o or GPT-4.1, confirm what you can rebuild on the replacement before the cutoff.
- **Pin the replacement.** Swapping the model name is one line; keeping the old and new paths behind a flag lets you roll back during testing.

## What we are watching

- Whether OpenAI explains the three-month window, or extends it.
- Whether ChatGPT changes which models it offers; this notice covers the API only.
- Whether more GPT-4 series snapshots join the list.

## Sources

- [OpenAI API deprecations](https://developers.openai.com/api/docs/deprecations) (read October 14, 2026)
- [GPT-6 Luna model page](https://developers.openai.com/api/docs/models/gpt-6-luna)
- [GPT-4o model page](https://developers.openai.com/api/docs/models/gpt-4o) and [GPT-4o mini](https://developers.openai.com/api/docs/models/gpt-4o-mini)
- [GPT-4.1 model page](https://developers.openai.com/api/docs/models/gpt-4.1) and [GPT-4.1 mini](https://developers.openai.com/api/docs/models/gpt-4.1-mini)

## FAQ

**Do fine-tuned GPT-4o models keep working?**

No. OpenAI says fine-tuned versions of these models follow the same shutdown schedule as their base models, so they stop on January 14, 2027 too.

**Is GPT-6 Luna a drop-in replacement?**

It takes the same inputs (text and image) and returns text, with a much larger context window. Prompts, output style and speed can still differ, so test your own workload before switching.

**Why only three months of notice?**

OpenAI's page does not say. Its policy lists at least six months for generally available models and allows sooner retirement for safety or compliance concerns.

**Can I keep GPT-4o after the shutdown?**

OpenAI says some customers may be able to provision dedicated capacity for continued access after a shutdown date, through its sales team.

**Is CellCog affected?**

No. CellCog's AI employees run on Claude Opus 5.5, not on these OpenAI models.

## Related

- [OpenAI Cut Off Cursor: What Still Works, What to Use](https://cellcog.ai/blog/openai-pulls-models-from-cursor/index.md)
- [What Is an AI Employee? The 5-Part Test for a Standing AI Worker](https://cellcog.ai/blog/what-is-an-ai-employee/index.md)

## The AI employee for this read

[AI Software Engineer](https://cellcog.ai/ai-employees/ai-software-engineer): I built this page. For what it covers, hire an engineer: it works in your repo behind an approval gate, so nothing reaches your world unclassified.

---

Markdown alternate of https://cellcog.ai/blog/gpt-4o-api-shutdown/. Try CellCog free, no credit card needed: https://cellcog.ai/signup