gpt-oss-20b vs Phi-4 Reasoning Vision 15B
gpt-oss-20b (2025) and Phi-4 Reasoning Vision 15B (2026) are general-purpose language models from OpenAI and Microsoft Research. gpt-oss-20b ships a 131k-token context window, while Phi-4 Reasoning Vision 15B ships a not-yet-sourced 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.
Phi-4 Reasoning Vision 15B is safer overall; choose gpt-oss-20b when provider fit matters.
Decision scorecard
Local evidence first| Signal | gpt-oss-20b | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Best for | tool-calling agents and provider-routed production | multimodal apps |
| Decision fit | RAG, Agents, and Long context | Vision |
| Context window | 131k | — |
| Cheapest output | $0.14/1M tokens | - |
| Provider routes | 9 tracked | 0 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- gpt-oss-20b has the larger context window for long prompts, retrieval packs, or transcript analysis.
- gpt-oss-20b has broader tracked provider coverage for fallback and procurement flexibility.
- gpt-oss-20b uniquely exposes Function calling, Tool use, and Structured outputs in local model data.
- Local decision data tags gpt-oss-20b for RAG, Agents, and Long context.
- Phi-4 Reasoning Vision 15B uniquely exposes Multimodal in local model data.
- Local decision data tags Phi-4 Reasoning Vision 15B for Vision.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
gpt-oss-20b
$59.00
Cheapest tracked route/tier: OpenRouter
Phi-4 Reasoning Vision 15B
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 gpt-oss-20b and Phi-4 Reasoning Vision 15B; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Function calling, Tool use, and Structured outputs before moving production traffic.
- Phi-4 Reasoning Vision 15B adds Multimodal in local capability data.
- No overlapping tracked provider route is sourced for Phi-4 Reasoning Vision 15B and gpt-oss-20b; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Multimodal before moving production traffic.
- gpt-oss-20b adds Function calling, Tool use, and Structured outputs in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-08-05 | 2026-03-12 |
| Context window | 131k | — |
| Parameters | 20B | 15B |
| Architecture | decoder only | - |
| License | Open Weights | Microsoft Research |
| Knowledge cutoff | 2025-08 | 2025-03 |
Pricing and availability
| Pricing attribute | gpt-oss-20b | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Input price | $0.03/1M tokens | - |
| Output price | $0.14/1M tokens | - |
| Providers | - |
Capabilities
| Capability | gpt-oss-20b | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Vision | No | No |
| Multimodal | No | Yes |
| Reasoning | No | No |
| 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 multimodal input: Phi-4 Reasoning Vision 15B, function calling: gpt-oss-20b, tool use: gpt-oss-20b, and structured outputs: gpt-oss-20b. 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: gpt-oss-20b has $0.03/1M input tokens and Phi-4 Reasoning Vision 15B has no token price sourced yet. Provider availability is 9 tracked routes versus 0. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose gpt-oss-20b when provider fit and broader provider choice are central to the workload. Choose Phi-4 Reasoning Vision 15B when provider fit 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
Is gpt-oss-20b or Phi-4 Reasoning Vision 15B open source?
gpt-oss-20b is listed under Open Weights. Phi-4 Reasoning Vision 15B is listed under Microsoft Research. 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 multimodal input, gpt-oss-20b or Phi-4 Reasoning Vision 15B?
Phi-4 Reasoning Vision 15B 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 function calling, gpt-oss-20b or Phi-4 Reasoning Vision 15B?
gpt-oss-20b 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, gpt-oss-20b or Phi-4 Reasoning Vision 15B?
gpt-oss-20b 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.
Which is better for structured outputs, gpt-oss-20b or Phi-4 Reasoning Vision 15B?
gpt-oss-20b has the clearer documented structured outputs signal in this comparison. If structured outputs is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run gpt-oss-20b and Phi-4 Reasoning Vision 15B?
gpt-oss-20b is available on Cloudflare Workers AI, OpenRouter, Fireworks AI, GCP Vertex AI, and NVIDIA NIM. Phi-4 Reasoning Vision 15B 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: 2026-05-22. Data sourced from public model cards and provider documentation.