Codex 1 vs Phi-4 Reasoning Vision 15B
Codex 1 (2025) and Phi-4 Reasoning Vision 15B (2026) compare a coding-specialized model against a standalone API model. Codex 1 ships a 192k-token context window, while Phi-4 Reasoning Vision 15B ships a not-yet-sourced context window. This page treats the result as workflow and deployment fit, not a universal model winner.
Treat this as a product-type comparison: Codex 1 is coding-specialized model, while Phi-4 Reasoning Vision 15B is standalone API model. Choose based on workflow fit before reading any benchmark or price row as decisive.
Decision scorecard
Local evidence first| Signal | Codex 1 | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Product type | Coding-specialized model | Standalone API model |
| Best for | custom coding agents and code generation | multimodal apps |
| Decision fit | Coding, Agents, and Long context | Vision |
| Context window | 192k | — |
| Cheapest output | - | - |
| Provider routes | 0 tracked | 0 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Codex 1 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Codex 1 uniquely exposes Reasoning and Code execution in local model data.
- Local decision data tags Codex 1 for Coding, Agents, and Long context.
- Phi-4 Reasoning Vision 15B uniquely exposes Vision and 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.
Codex 1
Unavailable
No complete token price in local provider data
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 Codex 1 and Phi-4 Reasoning Vision 15B; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Reasoning and Code execution before moving production traffic.
- Phi-4 Reasoning Vision 15B adds Vision and Multimodal in local capability data.
- No overlapping tracked provider route is sourced for Phi-4 Reasoning Vision 15B and Codex 1; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Vision and Multimodal before moving production traffic.
- Codex 1 adds Reasoning and Code execution in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-05-16 | 2026-03-12 |
| Context window | 192k | — |
| Parameters | — | 15B |
| Architecture | decoder only | - |
| License | Proprietary | MIT(OSI) |
| Openness | Proprietary | Open source |
| Commercial use | Commercial use with conditions | Commercial use allowed |
| Knowledge cutoff | - | 2025-03 |
Pricing and availability
| Pricing attribute | Codex 1 | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Input price | - | - |
| Output price | - | - |
| Providers | - | - |
Pricing not yet sourced for either model.
Capabilities
| Capability | Codex 1 | Phi-4 Reasoning Vision 15B |
|---|---|---|
| Vision | No | Yes |
| Multimodal | No | Yes |
| Reasoning | Yes | No |
| Function calling | No | No |
| Tool use | No | No |
| Structured outputs | No | No |
| Code execution | Yes | 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: Phi-4 Reasoning Vision 15B, multimodal input: Phi-4 Reasoning Vision 15B, reasoning mode: Codex 1, and code execution: Codex 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: Codex 1 has no token price sourced yet and Phi-4 Reasoning Vision 15B has no token price sourced yet. Provider availability is 0 tracked routes versus 0. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose Codex 1 when coding workflow support are central to the workload. Choose Phi-4 Reasoning Vision 15B when vision-heavy evaluation 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 Codex 1 or Phi-4 Reasoning Vision 15B open source?
Codex 1 is listed under Proprietary. Phi-4 Reasoning Vision 15B is listed under MIT. 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, Codex 1 or Phi-4 Reasoning Vision 15B?
Phi-4 Reasoning Vision 15B 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.
Which is better for multimodal input, Codex 1 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 reasoning mode, Codex 1 or Phi-4 Reasoning Vision 15B?
Codex 1 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 code execution, Codex 1 or Phi-4 Reasoning Vision 15B?
Codex 1 has the clearer documented code execution signal in this comparison. If code execution is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
When should I pick Codex 1 over Phi-4 Reasoning Vision 15B?
Treat this as a product-type comparison: Codex 1 is coding-specialized model, while Phi-4 Reasoning Vision 15B is standalone API model. Choose based on workflow fit before reading any benchmark or price row as decisive. If your workload also depends on coding workflow support, start with Codex 1; if it depends on vision-heavy evaluation, run the same evaluation with Phi-4 Reasoning Vision 15B.
Continue comparing
Last reviewed: 2026-06-04. Data sourced from public model cards and provider documentation.