xAI announced the retirement of several earlier Grok models from its API, effective May 15, 2026, at 12:00 PM PT. This move aims to concentrate development on the newest generation of Grok models. After this date, requests to the retired model slugs will automatically redirect to grok-4.3 or grok-build-0.1, depending on the original model.
Key Points
- Several Grok models will be retired from the xAI API on May 15, 2026, at 12:00 PM PT.
- Retired models include grok-4-1-fast-reasoning, grok-4-fast-reasoning, grok-4-0709, grok-4-1-fast-non-reasoning, grok-4-fast-non-reasoning, and grok-code-fast-1.
- Requests to retired reasoning models will redirect to grok-4.3 with low reasoning effort.
- Requests to retired non-reasoning models will redirect to grok-4.3 with none reasoning effort.
- Requests to grok-code-fast-1 will redirect to grok-build-0.1.
- grok-4.3 is priced at $1.25 per 1M input tokens and $2.50 per 1M output tokens.
- grok-4.3 offers four reasoning effort levels: none, low, medium, and high.
Context
According to xAI, the retirement of these models allows the company to focus fully on its newest generation of Grok. The slugs for the retired models will continue to resolve, meaning existing code will not break, but requests will be routed to the newer models.
Why It Matters
Developers using the xAI API must update their model configurations before May 15, 2026, to avoid unexpected cost increases due to new pricing for grok-4.3 and to explicitly control the reasoning effort applied to their workloads.
What To Do
- Explicitly update the "model" field in API requests to specify the desired replacement model before May 15, 2026.
- Compare the pricing of grok-4.3 ($1.25 per 1M input tokens and $2.50 per 1M output tokens) with the rates of the original models.
- For workloads previously using grok-4-1-fast-reasoning, grok-4-fast-reasoning, or grok-4-0709, migrate to grok-4.3.
- For workloads previously using grok-4-1-fast-non-reasoning or grok-4-fast-non-reasoning, migrate to grok-4.3 with none reasoning effort.
- For workloads previously using grok-code-fast-1, migrate to grok-build-0.1.