GPT-5.5 Pro
Last separately-billed "-pro" API id; for GPT-5.6/GPT-6 OpenRouter exposes pro as reasoning.mode pro. Snapshot gpt-5.5-pro-2026-04-23. Azure id not verified.
- Context window
- 1,050,000 tokens
- Max output
- 128,000 tokens
- Knowledge cutoff
- 2025-12
- Input
- text, image
- Output
- text
- License
- proprietary
- Pricing
- input: $30 · output: $180 (per 1M tokens (USD), no cached-input discount) source
- Verified
- 2026-09-29
How to call it
| Provider | Model id | Endpoint / URL | Docs |
|---|---|---|---|
| OpenAI API | gpt-5.5-pro | https://api.openai.com/v1/responses | docs |
| OpenRouter | openai/gpt-5.5-pro | openrouter.ai/openai/gpt-5.5-pro | — |
| Web app | — | chatgpt.com | — |
Notable capabilities (2)
- Extended compute: Uses more compute per request; some requests take several minutes. Effort medium/high/xhigh. source
- Responses/Batch only: Not available on Chat Completions. source
Hardest problems where latency does not matter.
curl https://api.openai.com/v1/responses \
-H "Authorization: Bearer $OPENAI_API_KEY" -H "Content-Type: application/json" \
-d '{"model":"gpt-5.5-pro","input":"Hello"}'
Sources:
Other OpenAI models
GPT-6 Luna · GPT-6 Sol · GPT Image 2.5 Flare · GPT Image 2.5 Sunburst · GPT-6 Astra · GPT-Live-Transcribe · GPT-Transcribe · GPT-5.6 Terra · GPT-Live 1 · GPT-Realtime-2.1 · GPT-Realtime-2 · GPT-Realtime-Translate · GPT-Rosalind · GPT-Audio-1.5 (and gpt-audio / gpt-audio-mini) · GPT-5.3-Codex · gpt-oss-120b · gpt-oss-20b · GPT-4o mini TTS · text-embedding-3-large · text-embedding-3-small · GPT-5.6 Luna · GPT-5.6 Sol · GPT-Realtime-Whisper · GPT-5.5 · GPT Image 2 · GPT-5.4 · GPT-Realtime-1.5 · GPT-4.1 · GPT-4o · TTS-1 / TTS-1 HD · Whisper large-v3 / large-v3-turbo (open weights) · GPT-Realtime and GPT-Realtime mini · o3 · GPT-4o Transcribe / Mini Transcribe / Transcribe Diarize · Whisper (whisper-1 API) · Sora 2