What happens to my existing Threads after the Assistants API shuts down?

OpenAI does not move them for you. The migration guide says outright that OpenAI will not provide an automated tool for migrating Threads to Conversations, and recommends putting new user threads onto conversations while migrating older ones only as necessary. Any conversation history you want to keep has to be exported and recreated by hand.

Is there an extension to the Assistants API deadline?

None has been offered. OpenAI announced the Assistants API beta deprecation on August 26, 2025 with a sunset exactly one year later, on August 26, 2026, and the announcement post mentions no extension and no provision for data export. The deprecations page lists the same shutdown date with the Responses API and Conversations API as the replacement.

How does the Responses API differ from the Assistants API?

The Responses API drops the threads-and-runs machinery for a direct input-and-output model: you send input items and get output items back. OpenAI says it deprecated the Assistants API only after the Responses API reached feature parity, and describes the newer API as simpler, more flexible, and faster.

Which capabilities did OpenAI move into the Responses API?

Code interpreter and persistent conversations carried over from the Assistants API, and the Responses API adds deep research, MCP, and computer use on top. Those additions are part of why OpenAI treats the Responses API as a full replacement rather than a parallel option, and why the Assistants beta was retired rather than kept running.

OpenAI · 2026-08-26 · major

OpenAI Assistants API shuts down — the beta ends one year after notice

OpenAI removes the Assistants API on August 26, 2026, one year after telling developers it would. The replacement is the Responses API paired with the Conversations API, and there is no automated tool to move existing Threads across.

OpenAI developer docs page for the Assistants API migration guide

OpenAI's Assistants API reaches its sunset date today, and the Responses API plus the Conversations API take over.

Quick facts

Removed API	Assistants API (beta)
Announced	August 26, 2025
Shutdown	August 26, 2026
Replacement	Responses API + Conversations API
Object mapping	Assistants→Prompts, Threads→Conversations, Runs→Responses, Run steps→Items
Thread migration	No automated tool provided

What is it?

The Assistants API is removed from OpenAI's platform on August 26, 2026, exactly one year after the deprecation notice went up. OpenAI deprecated the beta once the Responses API reached feature parity, including code interpreter and persistent conversations. By OpenAI's own account, the Responses API had already overtaken Chat Completions in token activity when the notice was posted.

How does it work?

Migration is a rename of four object types plus a rewrite of the call flow. Assistants become Prompts, Threads become Conversations, Runs become Responses, and Run steps become Items. In client code that means openai.beta.threads.create() gives way to openai.conversations.create(), and openai.beta.threads.runs.create() gives way to openai.responses.create(). Prompts are built from existing assistants in the dashboard.

Why does it matter?

Production code still calling the Assistants API stops working once the removal lands, and the stored history does not follow it. OpenAI states plainly that it will not provide an automated tool for migrating Threads to Conversations, and its guide recommends putting new user threads on conversations while moving older ones only as needed — so the cleanup is manual and open-ended.

Who is it for?

developers running OpenAI agent apps

Frequently asked questions

What happens to my existing Threads after the Assistants API shuts down?: OpenAI does not move them for you. The migration guide says outright that OpenAI will not provide an automated tool for migrating Threads to Conversations, and recommends putting new user threads onto conversations while migrating older ones only as necessary. Any conversation history you want to keep has to be exported and recreated by hand.
Is there an extension to the Assistants API deadline?: None has been offered. OpenAI announced the Assistants API beta deprecation on August 26, 2025 with a sunset exactly one year later, on August 26, 2026, and the announcement post mentions no extension and no provision for data export. The deprecations page lists the same shutdown date with the Responses API and Conversations API as the replacement.
How does the Responses API differ from the Assistants API?: The Responses API drops the threads-and-runs machinery for a direct input-and-output model: you send input items and get output items back. OpenAI says it deprecated the Assistants API only after the Responses API reached feature parity, and describes the newer API as simpler, more flexible, and faster.
Which capabilities did OpenAI move into the Responses API?: Code interpreter and persistent conversations carried over from the Assistants API, and the Responses API adds deep research, MCP, and computer use on top. Those additions are part of why OpenAI treats the Responses API as a full replacement rather than a parallel option, and why the Assistants beta was retired rather than kept running.

Try it

openai.conversations.create() plus openai.responses.create() replace the threads-and-runs pair