GPT Realtime 2 vs Phi-4 Reasoning Vision 15B
GPT Realtime 2 (2026) and Phi-4 Reasoning Vision 15B (2026) are frontier reasoning models from OpenAI and Microsoft Research. GPT Realtime 2 ships a 131K-token context window, while Phi-4 Reasoning Vision 15B ships a not-yet-sourced context window. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing.
GPT Realtime 2 is safer overall; choose Phi-4 Reasoning Vision 15B when provider fit matters.
Decision scorecard
Local evidence first| Signal | GPT Realtime 2 | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Decision fit | RAG, Agents, and Long context | Vision |
| Context window | 131K | — |
| Cheapest output | $64/1M tokens | - |
| Provider routes | 1 tracked | 0 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- GPT Realtime 2 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT Realtime 2 has broader tracked provider coverage for fallback and procurement flexibility.
- GPT Realtime 2 uniquely exposes Reasoning, Function calling, and Tool use in local model data.
- Local decision data tags GPT Realtime 2 for RAG, Agents, and Long context.
- 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 prices on this page.
GPT Realtime 2
$41,600
Cheapest tracked route: OpenAI API
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 Realtime 2 and Phi-4 Reasoning Vision 15B; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Reasoning, Function calling, and Tool use before moving production traffic.
- No overlapping tracked provider route is sourced for Phi-4 Reasoning Vision 15B and GPT Realtime 2; plan for SDK, billing, or endpoint changes.
- GPT Realtime 2 adds Reasoning, Function calling, and Tool use in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-05-07 | 2026-03-12 |
| Context window | 131K | — |
| Parameters | — | 15B |
| Architecture | decoder only | - |
| License | Proprietary | Microsoft Research |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | GPT Realtime 2 | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Input price | $32/1M tokens | - |
| Output price | $64/1M tokens | - |
| Providers | - |
Capabilities
| Capability | GPT Realtime 2 | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Vision | No | No |
| Multimodal | Yes | Yes |
| Reasoning | Yes | No |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | No | No |
| Code execution | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on reasoning mode: GPT Realtime 2, function calling: GPT Realtime 2, and tool use: GPT Realtime 2. Both models share multimodal input, 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 Realtime 2 has $32/1M input tokens and Phi-4 Reasoning Vision 15B has no token price sourced yet. Provider availability is 1 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 Realtime 2 when reasoning depth 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.
FAQ
Is GPT Realtime 2 or Phi-4 Reasoning Vision 15B open source?
GPT Realtime 2 is listed under Proprietary. 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 Realtime 2 or Phi-4 Reasoning Vision 15B?
Both GPT Realtime 2 and Phi-4 Reasoning Vision 15B expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Which is better for reasoning mode, GPT Realtime 2 or Phi-4 Reasoning Vision 15B?
GPT Realtime 2 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, GPT Realtime 2 or Phi-4 Reasoning Vision 15B?
GPT Realtime 2 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 Realtime 2 or Phi-4 Reasoning Vision 15B?
GPT Realtime 2 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 GPT Realtime 2 and Phi-4 Reasoning Vision 15B?
GPT Realtime 2 is available on OpenAI API. 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: 2026-05-16. Data sourced from public model cards and provider documentation.