API
OpenAI
OpenAI has deprecated the Assistants API and will remove it from the platform on 26 August 2026, directing developers to the newer Responses API
departs 26 Aug 2026
What this means for you
The Assistants API — the assistants, threads, and runs objects plus the built-in file_search and code_interpreter tools — is the framework a large number of teams built agent, chatbot, and document-QA features on after it launched in 2023. OpenAI deprecated it on 26 August 2025 and set 26 August 2026 as the day it is removed from the platform. Deprecated means it keeps working until then; on the shutdown date, calls to the /v1/assistants, /v1/threads, and related endpoints stop responding. Any product that stores conversation state as OpenAI-hosted Threads, or defines a bot's behavior and tools through an Assistant object, breaks on that date unless it has been migrated. Nothing changes the day you read this — the one-year window from the 2025 announcement is the runway to move.
Where to go
OpenAI's designated successor is the Responses API, and this is a genuine re-architecture rather than a find-and-replace. The Assistants API is stateful in a particular way: OpenAI persists your Assistant, Thread, and Run objects and you reference them by ID. The Responses API models the same capabilities — tool use, file search, code execution, multi-turn state — through a different, single-endpoint shape, so porting means rebuilding how you manage conversation state and re-wiring each built-in tool, not swapping a string. Budget real engineering time, migrate behind the same product surface, and validate well before 26 August 2026 rather than treating it as a last-minute cutover. Teams unwilling to track OpenAI's platform cadence can evaluate other agent frameworks, but that is a larger move than adopting the Responses API.
- OpenAI Responses API — the official successor OpenAI points Assistants users to
If your product runs an AI agent, a chat assistant, or a document-question feature, there is a real chance it was built on OpenAI’s Assistants API — the set of assistants, threads, and runs objects, with file_search and code_interpreter bundled in, that launched in 2023 and became many teams’ default way to ship an assistant without managing conversation state themselves.
OpenAI deprecated that API on 26 August 2025 and gave it a hard removal date of 26 August 2026. Deprecation is a warning, not an outage: the endpoints keep working through that window. The change that matters is dated — on the shutdown date, calls to /v1/assistants, /v1/threads, and their relatives stop responding, and anything that leans on OpenAI-hosted Threads for conversation memory or on an Assistant object for its behavior fails.
The migration target is OpenAI’s Responses API, and it is worth being honest that this is a re-architecture, not a rename. The Assistants API kept your Assistant, Thread, and Run objects on OpenAI’s side and let you reference them by ID; the Responses API delivers the same capabilities — tool use, file search, code execution, multi-turn state — through a different single-endpoint shape. Porting means rebuilding how conversation state is stored and re-wiring each built-in tool, then re-testing the whole flow. None of that is exotic, but it is not a string swap either.
The good news is the runway. A full year separates the announcement from the shutdown, which is ample time to migrate behind the same product surface and validate. The trap here is the usual one — a stable integration that works for months, then throws on a single morning in late August 2026 because the endpoint it calls no longer exists. Treat the date as a dependency deadline and move before it, not after.
Entry changelog
- — last reviewed.
- — Entry created from OpenAI's official API deprecations page. Deprecation announced 26 August 2025; removal 26 August 2026. Surfaced via Layer-2 discovery, written from OpenAI's primary deprecations list.
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