Grok Model Retirement on May 15, 2026

As we continue advancing Grok, we are retiring several earlier models to focus fully on our newest generation. Effective May 15, 2026 at 12:00 PM PT, the following models will be retired from the xAI API:

• grok-4-1-fast-reasoning
• grok-4-1-fast-non-reasoning
• grok-4-fast-reasoning
• grok-4-fast-non-reasoning
• grok-4-0709
• grok-code-fast-1
• grok-3
• grok-imagine-image-pro

Starting May 15, 2026 at 12:00 PM PT:

• Requests to any reasoning model in the list above will be served by grok-4.3 with low reasoning effort.
• Requests to any non-reasoning model in the list above will be served by grok-4.3 with none reasoning effort.
• grok-imagine-image-pro will be redirected to grok-imagine-image-quality.

If you continue sending requests to a deprecated slug after May 15, please be aware that you will be billed at grok-4.3 pricing of $1.25 per 1M input tokens and $2.50 per 1M output tokens rather than the rates of the original model.

To avoid unexpected cost increases, we recommend explicitly choosing the right replacement model for each workload before May 15. See the recommended replacements below.

We have newer, more capable models ready for every workload. In most cases, migrating is as simple as changing the "model" field in your API request. Doing so explicitly lets you control which reasoning effort you pay for, rather than accepting the default applied by the redirect.

If you are using grok-4-1-fast-reasoning, grok-4-fast-reasoning, or grok-4-0709, we recommend migrating to grok-4.3.

Grok 4.3 is the fastest, most intelligent model we have ever built. It tops the leaderboards in agentic tool calling and instruction following, and includes:

• 1 million token context window
• 4 reasoning effort levels (none, low, medium, and high)
• Priced at $1.25 / 1M input and $2.50 / 1M output

After May 15, requests to these slugs are routed to grok-4.3 with low reasoning effort. If your workload benefits from deeper reasoning, set medium or high reasoning effort explicitly on your requests.

If you are using grok-4-1-fast-non-reasoning or grok-4-fast-non-reasoning, we recommend migrating to grok-4.3 with none reasoning effort, which is also where these slugs are redirected after May 15.

For less latency-sensitive workloads, consider using grok-4.3 with low reasoning effort.

If you are using grok-code-fast-1, we recommend migrating to grok-build-0.1, which delivers significantly improved agentic coding and web dev capabilities. After May 15, requests to grok-code-fast-1 are routed to grok-build-0.1.

We are here to support you through this migration. If you have any questions or need assistance, please reach out to support@x.ai.