GPT-5.5 Pro

Model ID

gpt-5.5-pro

Provider

OpenAI

Context

1,050,000-token context window · 128,000 max output tokens

Capabilities

Streaming, JSON mode, Tool calling, Vision, Reasoning, Long context, Multilingual

OpenAI’s highest-accuracy GPT-5.5 variant for difficult reasoning, tool use, and long-context professional work.

Pricing

Input	Output	Cached input	Cache write
$30.00 / MTok	$180.00 / MTok	$30.00 / MTok	$30.00 / MTok

Typical request (5K input / 1K output tokens): ~$0.33. Billing is metered per token. Prices are live at GET /api/v1/models/gpt-5.5-pro; the values above were read from that endpoint when this page was generated.

Use this model

The SDK examples assume you have created a server-side client.

const completion = await client.chat.completions.create({
  model: "gpt-5.5-pro",
  messages: [{ role: "user", content: "Explain edge caching in one paragraph." }],
});

console.log(completion.choices[0].message.content);

completion = client.chat.completions.create(
    model="gpt-5.5-pro",
    messages=[{"role": "user", "content": "Explain edge caching in one paragraph."}],
)

print(completion["choices"][0]["message"]["content"])

curl https://www.ninjachat.ai/api/v1/chat/completions \
  -H "Authorization: Bearer $NINJACHAT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"gpt-5.5-pro","messages":[{"role":"user","content":"Explain edge caching in one paragraph."}]}'

Supported parameters

messages, temperature, max_completion_tokens, top_p, stop, frequency_penalty, presence_penalty, seed, stream, user, routing, tools, tool_choice, response_format, image_url content parts, reasoning, reasoning_effort Send only parameters from this list. routing.require_parameters (default true) skips any provider rail that cannot honor every requested parameter, so unsupported parameters reduce the rails eligible to serve the request.

Routing & fallbacks

Pin gpt-5.5-pro with model when you want this model’s behavior, or list it in an ordered models array. With ninja/auto first, the router’s top pick runs first and gpt-5.5-pro is the explicit fallback; ninja/auto acts as the router only when it is the first entry.

{
  "models": [
    "ninja/auto",
    "gpt-5.5-pro"
  ],
  "messages": [
    {
      "role": "user",
      "content": "Explain edge caching in one paragraph."
    }
  ],
  "routing": {
    "allow_fallbacks": true
  }
}

You are billed at the resolved model’s token rates, and only for the successful execution.

Check live support

TypeScript SDK

const model = await client.models.retrieve("gpt-5.5-pro");

if (!model.servable) throw new Error("gpt-5.5-pro is temporarily unavailable");

console.log({
  contextWindow: model.contextWindow,
  maxOutputTokens: model.maxOutputTokens,
  capabilities: model.capabilities,
  supportedParameters: model.supportedParameters,
  pricing: model.pricing,
  providers: model.providers,
});

Guides: Text generation · Fallbacks · Smart routing · Pricing · All models

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Pricing

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Routing & fallbacks

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Model ID

Provider

Context

Capabilities

​Pricing

​Use this model

​Supported parameters

​Routing & fallbacks

​Check live support

Pricing

Use this model

Supported parameters

Routing & fallbacks

Check live support