OpenAI Shutdown Deadlines 2026: Assistants API Aug 26, Prompts Nov 30 + 5 More

On 2026-08-26 — two days from now — OpenAI’s Assistants API shuts down. Not degraded, not throttled: the endpoints stop serving.

But the thing worth looking at first is something else entirely: the destination the official migration guide points you toward has its own shutdown date.

This piece lays out the seven deadlines on OpenAI’s official deprecations page, running from Aug 26 through 2027-01-20, with the announcement date, shutdown date, affected endpoints and official replacement for each row. All read directly from official docs, verified 2026-08-24.

The urgent one: Assistants API shuts down Aug 26

• Announced: 2025-08-26
• Shutdown: 2026-08-26 (a full year of runway)
• Official replacement: Responses API + Conversations API

The deprecations page words it this way: “When we released the Responses API in March 2025, we announced plans to bring all Assistants API features to the easier to use Responses API, with a sunset date in 2026.”

Concept mapping, from the official migration guide:

Worth flagging: the migration guide states plainly that no automated tool is provided to convert Threads into Conversations. What it gives you is Python and Ruby sample code for manual backfill, plus the advice to put new user threads onto Conversations and migrate older ones as needed. So if your service still runs on Assistants, not finishing a full bulk migration in two days is normal — prioritise routing new traffic to the new endpoints and backfill history afterwards.

The finding: the mapping’s destination is also on the clock

That table says Assistants → Prompts. But scroll down the same deprecations page:

Reusable prompts API: the v1/prompts API and reusable prompt objects are scheduled to shut down. Announced 2026-06-03, shutdown 2026-11-30. Official recommendation: move reusable prompt content into application code.

Follow the concept mapping literally — rewrite your Assistant definitions as reusable prompt objects — and you get to do the migration again 96 days later (Aug 26 to Nov 30).

The safer move: put your Assistant’s instructions and tool definitions directly into your application code now, and pass them as parameters on each Responses API call, skipping the reusable prompt object entirely. OpenAI’s own recommendation for the Nov 30 deadline is that exact sentence — “move reusable prompt content into application code” — so the endpoint of the journey is already documented.

All seven deadlines (read from the official deprecations page, verified 2026-08-24)

Three details that are easy to miss

1. gpt-image-1 sits in the Oct 23 row, not Dec 1 It is easy to assume the image-model deadline is Dec 1. On the official table, gpt-image-1 is grouped into the Oct 23 legacy-snapshot batch — 39 days earlier than the Dec 1 date that covers gpt-image-1-mini, gpt-image-1.5 and chatgpt-image-latest. If your service is pinned to gpt-image-1, your real deadline is October, not December.

2. Sora 2 and the Videos API have no official replacement On the Sep 24 row, the deprecations page lists no recommended replacement. Every other row has one; this one is blank. If you generate video, you need your own plan — and that is the row deserving the earliest attention.

3. Agent Builder’s replacement forks in two directions For the Nov 30 Agent Builder shutdown, OpenAI names two paths: Agents SDK for code-driven work, ChatGPT Workspace Agents for the interface-driven case. These serve quite different use cases — do not assume a drop-in swap.

Does any of this affect regular users?

Not directly. Everything above is API- and developer-level: endpoints and model snapshots. It is separate from ChatGPT’s web and app subscription tiers (Free, Go, Plus, Pro), whose contents and prices are untouched by these deadlines.

What can reach you: a third-party AI product whose backend still runs on the Assistants API may start misbehaving after Aug 26. If some AI tool you rely on breaks in the next few days, that is a reasonable first thing to suspect.

What we would do

1. Within two days: check whether anything you run calls /v1/assistants or /v1/threads. If so, route new traffic to Responses + Conversations first.
2. Skip the Prompts object while migrating: put instructions in application code and save yourself the Nov 30 repeat.
3. Put Oct 23 in the calendar: that row covers the most models, and hardcoded model names hide well.
4. Settle your video plan before Sep 24: Sora 2 and the Videos API have no official replacement, so it needs the longest lead time.

All dates and model lists verified 2026-08-24, read directly from the OpenAI Deprecations page and the Assistants migration guide, cross-checked against the official OpenAI developer community announcement. OpenAI may revise these timelines at any point; the official pages are authoritative.

Related: GPT-5.6 Sol price cut, OpenAI ultrafast 14x, Agent Plugins 1.0 standard. Full plans and free quotas on our ChatGPT tool page.