GPT-5.5 Pro
GPT-5.5 Pro is the higher-compute GPT-5.5 tier for demanding research and professional questions. It launched in ChatGPT alongside GPT-5.5 before the API release. The tier aims for more accurate and comprehensive answers, using additional reasoning time and a higher token price. Its Responses API interface supports long-context, asynchronous work.
2026-04-23
Unreleased
Undisclosed proprietary architecture
Proprietary
Specifications
- Parameters
- Unreleased
- Architecture
- Undisclosed proprietary architecture
- License
- Proprietary
- Context Window
- 1,050,000 tokens
- Max Output
- 128,000 tokens
- Training Data Cutoff
- Dec 01, 2025
- Type
- multimodal
- Modalities
- textimage
Benchmark Scores
Advanced Specifications
- Model Family
- GPT-5
- API Access
- Available
- Chat Interface
- Not Available
- Variants
- gpt-5.5-pro-2026-04-23
Capabilities & Limitations
- Capabilities
- deep reasoningcodevisiontool use
- Known Limitations
- Can produce incorrect factual claims or code; important results require independent verification.Higher compute can increase response latency to several minutes.
- Notable Use Cases
- manuscript reviewdifficult researchprofessional analysis
- Function Calling Support
- Yes
- Tool Use Support
- Yes