Grok 4 Fast Reasoning vs Grok Code Fast 1
Grok 4 Fast Reasoning (2025) and Grok Code Fast 1 (2025) compare a standalone API model against a coding-specialized model. Grok 4 Fast Reasoning ships a 2m-token context window, while Grok Code Fast 1 ships a 262k-token context window. On pricing, Grok Code Fast 1 costs $0.20/1M input tokens versus $1.25/1M for the alternative. This page treats the result as workflow and deployment fit, not a universal model winner.
Treat this as a product-type comparison: Grok 4 Fast Reasoning is standalone API model, while Grok Code Fast 1 is coding-specialized model. Choose based on workflow fit before reading any benchmark or price row as decisive.
Decision scorecard
Local evidence first| Signal | Grok 4 Fast Reasoning | Grok Code Fast 1 |
|---|---|---|
| Product type | Standalone API model | Coding-specialized model |
| Best for | reasoning-heavy apps, multimodal apps, and long-context analysis | custom coding agents, code generation, and tool loops |
| Decision fit | Long context and Vision | Coding, RAG, and Agents |
| Context window | 2m | 262k |
| Cheapest output | $2.50/1M tokens | $1.50/1M tokens |
| Provider routes | 2 tracked | 3 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Grok 4 Fast Reasoning has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Grok 4 Fast Reasoning uniquely exposes Vision, Multimodal, and Reasoning in local model data.
- Local decision data tags Grok 4 Fast Reasoning for Long context and Vision.
- Grok Code Fast 1 has the lower cheapest tracked output price at $1.50/1M tokens.
- Grok Code Fast 1 has broader tracked provider coverage for fallback and procurement flexibility.
- Grok Code Fast 1 uniquely exposes Function calling, Tool use, and Structured outputs in local model data.
- Local decision data tags Grok Code Fast 1 for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Grok 4 Fast Reasoning
$1,625
Cheapest tracked route/tier: xAI Console
Grok Code Fast 1
$535
Cheapest tracked route/tier: OpenRouter
Estimated monthly gap: $1,090. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Microsoft Foundry and xAI Console; start route-level A/B tests there.
- Grok Code Fast 1 is $1/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision, Multimodal, and Reasoning before moving production traffic.
- Grok Code Fast 1 adds Function calling, Tool use, and Structured outputs in local capability data.
- Provider overlap exists on Microsoft Foundry and xAI Console; start route-level A/B tests there.
- Grok 4 Fast Reasoning is $1/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Function calling, Tool use, and Structured outputs before moving production traffic.
- Grok 4 Fast Reasoning adds Vision, Multimodal, and Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-09-01 | 2025-08-27 |
| Context window | 2m | 262k |
| Parameters | — | 314B |
| Architecture | decoder only | mixture of experts |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Commercial use | Commercial use with conditions | Commercial use with conditions |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | Grok 4 Fast Reasoning | Grok Code Fast 1 |
|---|---|---|
| Input price | $1.25/1M tokens | $0.20/1M tokens |
| Output price | $2.50/1M tokens | $1.50/1M tokens |
| Providers |
Capabilities
| Capability | Grok 4 Fast Reasoning | Grok Code Fast 1 |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | No |
| Function calling | No | Yes |
| Tool use | No | Yes |
| Structured outputs | No | Yes |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on vision: Grok 4 Fast Reasoning, multimodal input: Grok 4 Fast Reasoning, reasoning mode: Grok 4 Fast Reasoning, function calling: Grok Code Fast 1, tool use: Grok Code Fast 1, and structured outputs: Grok Code Fast 1. Both models share the core language-model surface, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, Grok 4 Fast Reasoning lists $1.25/1M input and $2.50/1M output tokens on the cheapest tracked provider, while Grok Code Fast 1 lists $0.20/1M input and $1.50/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Grok Code Fast 1 lower by about $1.04 per million blended tokens. Availability is 2 providers versus 3, so concentration risk also matters.
Choose Grok 4 Fast Reasoning when reasoning depth and larger context windows are central to the workload. Choose Grok Code Fast 1 when coding workflow support, lower input-token cost, and broader provider choice are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, Grok 4 Fast Reasoning or Grok Code Fast 1?
Grok 4 Fast Reasoning supports 2m tokens, while Grok Code Fast 1 supports 262k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Grok 4 Fast Reasoning or Grok Code Fast 1?
Grok Code Fast 1 is cheaper on tracked token pricing. Grok 4 Fast Reasoning costs $1.25/1M input and $2.50/1M output tokens. Grok Code Fast 1 costs $0.20/1M input and $1.50/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Grok 4 Fast Reasoning or Grok Code Fast 1 open source?
Grok 4 Fast Reasoning is listed under Proprietary. Grok Code Fast 1 is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, Grok 4 Fast Reasoning or Grok Code Fast 1?
Grok 4 Fast Reasoning has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for multimodal input, Grok 4 Fast Reasoning or Grok Code Fast 1?
Grok 4 Fast Reasoning has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Grok 4 Fast Reasoning and Grok Code Fast 1?
Grok 4 Fast Reasoning is available on Microsoft Foundry and xAI Console. Grok Code Fast 1 is available on OpenRouter, Microsoft Foundry, and xAI Console. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-20. Data sourced from public model cards and provider documentation.