Grok 4.3 vs Phi-4 Mini Reasoning
Grok 4.3 (2026) and Phi-4 Mini Reasoning (2026) are frontier-tier reasoning models from xAI and Microsoft Research. Grok 4.3 ships a 1M-token context window, while Phi-4 Mini Reasoning ships a 128K-token context window. On Google-Proof Q&A, Grok 4.3 leads by 38.1 pts. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing.
Grok 4.3 fits 8x more tokens; pick it for long-context work and Phi-4 Mini Reasoning for tighter calls.
Decision scorecard
Local evidence first| Signal | Grok 4.3 | Phi-4 Mini Reasoning |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | reasoning-heavy apps |
| Decision fit | RAG, Agents, and Long context | Long context |
| Context window | 1M | 128K |
| Cheapest output | $2.50/1M tokens | - |
| Provider routes | 4 tracked | 0 tracked |
| Shared benchmarks | Google-Proof Q&A leader | 1 rows |
Decision tradeoffs
- Grok 4.3 leads the largest shared benchmark signal on Google-Proof Q&A by 38.1 points.
- Grok 4.3 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Grok 4.3 has broader tracked provider coverage for fallback and procurement flexibility.
- Grok 4.3 uniquely exposes Vision, Multimodal, and Function calling in local model data.
- Local decision data tags Grok 4.3 for RAG, Agents, and Long context.
- 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 4.3
$1,625
Cheapest tracked route/tier: xAI Console
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 4.3 and Phi-4 Mini Reasoning; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Vision, Multimodal, and Function calling before moving production traffic.
- No overlapping tracked provider route is sourced for Phi-4 Mini Reasoning and Grok 4.3; plan for SDK, billing, or endpoint changes.
- Grok 4.3 adds Vision, Multimodal, and Function calling in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-05-06 | 2026-05-16 |
| Context window | 1M | 128K |
| Parameters | ~0.5T | 3.8B |
| Architecture | - | - |
| License | Proprietary | Proprietary |
| Knowledge cutoff | 2024-11 | 2025-02 |
Pricing and availability
| Pricing attribute | Grok 4.3 | Phi-4 Mini Reasoning |
|---|---|---|
| Input price |
| - |
| Output price |
| - |
| Providers | - |
Capabilities
| Capability | Grok 4.3 | Phi-4 Mini Reasoning |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | 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
| Benchmark | Grok 4.3 | Phi-4 Mini Reasoning |
|---|---|---|
| Google-Proof Q&A | 90.1 | 52.0 |
Deep dive
On shared benchmark coverage, Google-Proof Q&A has Grok 4.3 at 90.1 and Phi-4 Mini Reasoning at 52, with Grok 4.3 ahead by 38.1 points. The largest visible gap is 38.1 points on Google-Proof Q&A, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint differs most on vision: Grok 4.3, multimodal input: Grok 4.3, function calling: Grok 4.3, tool use: Grok 4.3, and structured outputs: Grok 4.3. Both models share reasoning mode, 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 4.3 has $1.25/1M input tokens and Phi-4 Mini Reasoning has no token price sourced yet. Provider availability is 4 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 4.3 when long-context analysis, larger context windows, and broader provider choice are central to the workload. Choose Phi-4 Mini Reasoning when provider fit 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 4.3 or Phi-4 Mini Reasoning?
Grok 4.3 supports 1M 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 4.3 or Phi-4 Mini Reasoning open source?
Grok 4.3 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 vision, Grok 4.3 or Phi-4 Mini Reasoning?
Grok 4.3 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. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, Grok 4.3 or Phi-4 Mini Reasoning?
Grok 4.3 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.
Which is better for reasoning mode, Grok 4.3 or Phi-4 Mini Reasoning?
Both Grok 4.3 and Phi-4 Mini Reasoning expose reasoning mode. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Where can I run Grok 4.3 and Phi-4 Mini Reasoning?
Grok 4.3 is available on xAI Console, OpenRouter, Microsoft Foundry, and Vercel AI Gateway. 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.
Continue comparing
Last reviewed: 2026-05-25. Data sourced from public model cards and provider documentation.