xAI Python SDK v1.12.1 adds grok-4.3 to the ChatModel list and reveals the next Grok iteration before any official announcement

On April 30, 2026, at 22:35 UTC, xAI released version v1.12.1 of its official Python SDK (xai-sdk-python). The release notes mention a brief but significant change: “Add grok-4.3 to ChatModel.” This is the first public trace of a new Grok iteration, predating any blog post or API endpoint documentation.

What does grok-4.3 mean for the xAI roadmap?

xAI traditionally announces new models via x.ai/news or x.ai/blog, but both subdomains remain Cloudflare-blocked for external WebFetch. docs.x.ai/docs/release-notes, which has been the most reliable public source for xAI changes, has not yet mentioned grok-4.3. The SDK is therefore the first indicator that xAI is technically ready to expose a new model via the ChatModel interface, even if the marketing announcement has not yet gone out. The sequence in xAI’s naming convention (3, 4, 4.20, 4.1 Fast) suggests that grok-4.3 is a point upgrade to the Grok 4 family, not the next major generation — but without a model card or benchmark data, this remains speculation.

What’s new in v1.12.0–v1.12.1

According to the CHANGELOG in the repository, v1.12.0 (April 29, 2026) brought three practical changes for SDK users: a new cost_usd field in API responses for per-call cost tracking, an expires_after parameter on the Files API for automatic deletion of uploaded files, and a default timeout of 27 minutes for synchronous calls. Version v1.12.1 builds on this by adding grok-4.3 to the ChatModel list and updating CHANGELOG entries for previously missed documentation.

How to track progress

Until xAI publishes an official blog post, the only ways to monitor developments are SDK release notes and the docs.x.ai/docs/models reference page. The pricing, context window, and benchmark performance of the grok-4.3 model will remain unknown until the first official communication.