Phi-4 Mini Flash Reasoning vs Qwen3.5-Flash
Phi-4 Mini Flash Reasoning (2025) and Qwen3.5-Flash (2026) are frontier reasoning models from Microsoft Research and Alibaba. Phi-4 Mini Flash Reasoning ships a 128k-token context window, while Qwen3.5-Flash ships a 1m-token context window. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads. It focuses on practical selection signals rather than broad model-family marketing.
Qwen3.5-Flash fits 8x more tokens; pick it for long-context work and Phi-4 Mini Flash Reasoning for tighter calls.
Decision scorecard
Local evidence first| Signal | Phi-4 Mini Flash Reasoning | Qwen3.5-Flash |
|---|---|---|
| Best for | reasoning-heavy apps | multimodal apps, long-context analysis, and provider-routed production |
| Decision fit | Long context | Long context, Vision, and Classification |
| Context window | 128k | 1m |
| Cheapest output | - | $0.26/1M tokens |
| Provider routes | 1 tracked | 3 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Phi-4 Mini Flash Reasoning uniquely exposes Reasoning in local model data.
- Local decision data tags Phi-4 Mini Flash Reasoning for Long context.
- Qwen3.5-Flash has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Qwen3.5-Flash has broader tracked provider coverage for fallback and procurement flexibility.
- Qwen3.5-Flash uniquely exposes Vision and Multimodal in local model data.
- Local decision data tags Qwen3.5-Flash for Long context, Vision, and Classification.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Phi-4 Mini Flash Reasoning
Unavailable
No complete token price in local provider data
Qwen3.5-Flash
$121
Cheapest tracked route/tier: OpenRouter
Cost delta unavailable until both models have sourced input and output token prices.
Switch friction
- No overlapping tracked provider route is sourced for Phi-4 Mini Flash Reasoning and Qwen3.5-Flash; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Reasoning before moving production traffic.
- Qwen3.5-Flash adds Vision and Multimodal in local capability data.
- No overlapping tracked provider route is sourced for Qwen3.5-Flash and Phi-4 Mini Flash Reasoning; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Vision and Multimodal before moving production traffic.
- Phi-4 Mini Flash Reasoning adds Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-12-01 | 2026-02-23 |
| Context window | 128k | 1m |
| Parameters | 3.8B | — |
| Architecture | decoder only | - |
| License | MIT(OSI) | Apache 2.0(OSI) |
| Openness | Open source | Open source |
| Commercial use | Commercial use allowed | Commercial use allowed |
| Knowledge cutoff | 2025-02 | - |
Pricing and availability
| Pricing attribute | Phi-4 Mini Flash Reasoning | Qwen3.5-Flash |
|---|---|---|
| Input price | - | $0.07/1M tokens |
| Output price | - | $0.26/1M tokens |
| Providers |
Capabilities
| Capability | Phi-4 Mini Flash Reasoning | Qwen3.5-Flash |
|---|---|---|
| Vision | No | Yes |
| Multimodal | No | Yes |
| Reasoning | Yes | No |
| Function calling | No | No |
| Tool use | No | No |
| Structured outputs | No | 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 vision: Qwen3.5-Flash, multimodal input: Qwen3.5-Flash, and reasoning mode: Phi-4 Mini Flash Reasoning. 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: Phi-4 Mini Flash Reasoning has no token price sourced yet and Qwen3.5-Flash has $0.07/1M input tokens. Provider availability is 1 tracked routes versus 3. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose Phi-4 Mini Flash Reasoning when reasoning depth are central to the workload. Choose Qwen3.5-Flash when long-context analysis, larger context windows, 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. 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. For teams standardizing a stack, that distinction is often the difference between a benchmark win and a reliable deployment.
FAQ
Which has a larger context window, Phi-4 Mini Flash Reasoning or Qwen3.5-Flash?
Qwen3.5-Flash supports 1m tokens, while Phi-4 Mini Flash 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 Phi-4 Mini Flash Reasoning or Qwen3.5-Flash open source?
Phi-4 Mini Flash Reasoning is listed under MIT. Qwen3.5-Flash is listed under Apache 2.0. 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, Phi-4 Mini Flash Reasoning or Qwen3.5-Flash?
Qwen3.5-Flash 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, Phi-4 Mini Flash Reasoning or Qwen3.5-Flash?
Qwen3.5-Flash 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, Phi-4 Mini Flash Reasoning or Qwen3.5-Flash?
Phi-4 Mini Flash 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.
Where can I run Phi-4 Mini Flash Reasoning and Qwen3.5-Flash?
Phi-4 Mini Flash Reasoning is available on NVIDIA NIM. Qwen3.5-Flash is available on Alibaba Cloud PAI-EAS, OpenRouter, and Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-06-04. Data sourced from public model cards and provider documentation.