Grok Code Fast 1 vs Phi-4 Mini Reasoning
Grok Code Fast 1 (2025) and Phi-4 Mini Reasoning (2026) compare a coding-specialized model against a standalone API model. Grok Code Fast 1 ships a 262K-token context window, while Phi-4 Mini Reasoning ships a 128K-token context window. This page treats the result as workflow and deployment fit, not a universal model winner.
Treat this as a product-type comparison: Grok Code Fast 1 is coding-specialized model, while Phi-4 Mini Reasoning is standalone API model. Choose based on workflow fit before reading any benchmark or price row as decisive.
Decision scorecard
Local evidence first| Signal | Grok Code Fast 1 | Phi-4 Mini Reasoning |
|---|---|---|
| Product type | Coding-specialized model | Standalone API model |
| Best for | custom coding agents, code generation, and tool loops | reasoning-heavy apps |
| Decision fit | Coding, RAG, and Agents | Long context |
| Context window | 262K | 128K |
| Cheapest output | $1.50/1M tokens | - |
| Provider routes | 3 tracked | 0 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Grok Code Fast 1 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- 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.
- Phi-4 Mini Reasoning uniquely exposes Reasoning in local model data.
- Local decision data tags Phi-4 Mini Reasoning for Long context.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Grok Code Fast 1
$535
Cheapest tracked route/tier: OpenRouter
Phi-4 Mini Reasoning
Unavailable
No complete token price in local provider data
Cost delta unavailable until both models have sourced input and output token prices.
Switch friction
- No overlapping tracked provider route is sourced for Grok Code Fast 1 and Phi-4 Mini Reasoning; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Function calling, Tool use, and Structured outputs before moving production traffic.
- Phi-4 Mini Reasoning adds Reasoning in local capability data.
- No overlapping tracked provider route is sourced for Phi-4 Mini Reasoning and Grok Code Fast 1; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Reasoning before moving production traffic.
- Grok Code Fast 1 adds Function calling, Tool use, and Structured outputs in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-08-27 | 2026-05-16 |
| Context window | 262K | 128K |
| Parameters | 314B | 3.8B |
| Architecture | mixture of experts | - |
| License | Proprietary | Proprietary |
| Knowledge cutoff | - | 2025-02 |
Pricing and availability
| Pricing attribute | Grok Code Fast 1 | Phi-4 Mini Reasoning |
|---|---|---|
| Input price | $0.20/1M tokens | - |
| Output price | $1.50/1M tokens | - |
| Providers | - |
Capabilities
| Capability | Grok Code Fast 1 | Phi-4 Mini Reasoning |
|---|---|---|
| Vision | No | No |
| Multimodal | No | No |
| Reasoning | No | Yes |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | Yes | No |
| 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 reasoning mode: Phi-4 Mini 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.
Pricing coverage is uneven: Grok Code Fast 1 has $0.20/1M input tokens and Phi-4 Mini Reasoning has no token price sourced yet. Provider availability is 3 tracked routes versus 0. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose Grok Code Fast 1 when coding workflow support, larger context windows, and broader provider choice are central to the workload. Choose Phi-4 Mini Reasoning when reasoning depth are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency.
FAQ
Which has a larger context window, Grok Code Fast 1 or Phi-4 Mini Reasoning?
Grok Code Fast 1 supports 262K tokens, while Phi-4 Mini Reasoning supports 128K tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Is Grok Code Fast 1 or Phi-4 Mini Reasoning open source?
Grok Code Fast 1 is listed under Proprietary. Phi-4 Mini Reasoning 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 reasoning mode, Grok Code Fast 1 or Phi-4 Mini Reasoning?
Phi-4 Mini Reasoning has the clearer documented reasoning mode signal in this comparison. If reasoning mode is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for function calling, Grok Code Fast 1 or Phi-4 Mini Reasoning?
Grok Code Fast 1 has the clearer documented function calling signal in this comparison. If function calling is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for tool use, Grok Code Fast 1 or Phi-4 Mini Reasoning?
Grok Code Fast 1 has the clearer documented tool use signal in this comparison. If tool use is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Grok Code Fast 1 and Phi-4 Mini Reasoning?
Grok Code Fast 1 is available on OpenRouter, Microsoft Foundry, and xAI Console. Phi-4 Mini Reasoning is available on the tracked providers still being sourced. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-05-22. Data sourced from public model cards and provider documentation.