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← AI PulseAug 20, 2026

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xAI Introduces Responses API, Deprecates Chat Completions

xAI has launched its Responses API as the recommended method for interacting with its models, while the legacy Chat Completions API is now deprecated.

By Illumora Editorial

Source · Aug 20, 2026, 3:13 PM · On Illumora · Aug 20, 2026, 4:03 PM

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Read the source →xAI Docs — Comparison with Chat Completions | SpaceXAI Docs
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xAI has introduced the Responses API as the primary interface for its models, according to xAI Docs. This new API replaces the Chat Completions API, which is now considered a legacy endpoint. New capabilities and features will be delivered through the Responses API first.

Key Points

  • The Responses API is the recommended method for interacting with xAI models.
  • The Chat Completions API is a deprecated legacy endpoint.
  • Response formats differ, with Responses API using an output array with typed items, unlike the choices[0].message.content structure of Chat Completions.
  • Responses API supports multi-turn conversations by allowing the use of previous_response_id.
  • The Chat Completions API requires resending the entire conversation history for multi-turn interactions.
  • Deferred chat completions, available via REST requests or the xAI SDK, allow retrieving a result once within 24 hours.
  • Deferred completion results are discarded after 24 hours if not retrieved.

Context

According to xAI Docs, the Chat Completions API was a popular feature used for tasks such as summarizing articles, generating creative writing, answering questions, providing customer support, and assisting with coding. However, new features will now prioritize the Responses API. Developers are advised to migrate to the new API, with migration guides available.

Why It Matters

Developers building with xAI models must transition to the Responses API to access new features and ensure compatibility. The change impacts how conversation history is managed and how responses are structured, requiring adjustments in application code.

What To Do

  • Review the xAI Docs for the Responses API to understand its structure and capabilities.
  • Consult the migration guide for transitioning from the Chat Completions API to the Responses API.
  • Note the new response format, which uses an output array with typed items.
  • Implement previous_response_id for multi-turn conversations when using the Responses API.
  • For long-running inference requests, explore deferred chat completions via REST requests or the xAI SDK, noting the 24-hour retrieval window.