Maximum-capability tier of the GPT-5.5 family (dated snapshot). Uses more compute to think longer and deliver the most reliable answers on the hardest reasoning, coding and analysis tasks. Served only via the OpenAI Responses API. $30/$180 per million tokens (no cached-input discount), flat across the full context window.
Test this model instantly in the Console Playground โ no code required
Copy usage instructions for Claude, ChatGPT, or other AI
| Token Type | Credits | USD Equivalent |
|---|---|---|
| Input Tokens | 55,740 | $37.16 |
| Output Tokens | 334,440 | $222.96 |
* 1,500 credits โ $1 (actual charges may vary based on usage)
curl -X POST "https://api.core.today/llm/openai/v1/responses" \
-H "Content-Type: application/json" \
-H "Authorization: Bearer cdt_your_api_key" \
-d '{
"model": "gpt-5.5-pro-2026-04-23",
"input": "Review this database migration plan for a zero-downtime rollout across 40 services and identify every failure mode with mitigations.",
"max_output_tokens": 16000
}'| Parameter | Type | Required | Default | Description |
|---|---|---|---|---|
model | string | Yes | gpt-5.5-pro-2026-04-23 | Model identifier (dated snapshot id) |
input | string | array | Yes | - | Responses API input: a plain string or an array of input items (messages, tool results) |
instructions | string | No | - | System-level instructions for the run |
max_output_tokens | integer | No | - | Maximum tokens in the response, including internal reasoning tokens (Responses API field; not max_tokens) |
reasoning | object | No | - | Reasoning options, e.g. { effort: "high" } |
stream | boolean | No | false | Enable Server-Sent Events streaming |
Maximum-effort analysis with GPT-5.5 Pro via the Responses API
curl -X POST "https://api.core.today/llm/openai/v1/responses" \
-H "Content-Type: application/json" \
-H "Authorization: Bearer cdt_your_api_key" \
-d '{
"model": "gpt-5.5-pro-2026-04-23",
"input": "Review this database migration plan for a zero-downtime rollout across 40 services and identify every failure mode with mitigations.",
"max_output_tokens": 16000
}'POST /llm/openai/v1/responses