GPT-5.5
OpenAIReleased Apr 24, 2026
GPT-5.5 is OpenAI’s frontier model designed for complex professional workloads, building on GPT-5.4 with stronger reasoning, higher reliability, and improved token efficiency on hard tasks. It features a 1M+ token...
- Context window
- 1.1M tokens
- Max output
- 128K tokens
- Input
- file, image, text
- Output
- text
- Tokenizer
- GPT
- Knowledge cutoff
- Dec 1, 2025
- Released
- Apr 24, 2026
- Reasoning
- optional
Pricing
Per 1M tokens. The provider price and our flat 3% fee are separate columns — what you pay is their sum.
| Per 1M tokens | Provider | + 3% fee | You pay |
|---|---|---|---|
| Input | $5.00 | $0.150 | $5.15 |
| Output | $30.00 | $0.900 | $30.90 |
| Cache read | $0.500 | $0.015 | $0.515 |
Benchmarks
Artificial Analysis
- Intelligence index
- 54.8
- Coding index
- 74.9
- Agentic index
- 44.9
Design Arena
| Category | Elo | Win rate | Rank |
|---|---|---|---|
| agenticgamedevagents | 1211 | 53.2% | #5 |
| agentichtmlslidesagents | 1084 | 34.2% | #9 |
| agenticslidesagents | 1150 | 43.5% | #7 |
| agenticslides(html)agents | 1077 | 33.2% | #9 |
| agenticslides(python-pptx)agents | 1155 | 45.2% | #7 |
| androidnativeagents | 1263 | 55.6% | #4 |
| Full-stackagents | 1154 | 44.6% | #15 |
| godotgamedevagents | 1217 | 53.2% | #9 |
| htmlslidesagents | 1082 | 34.1% | #11 |
| Mobile appsagents | 1227 | 51.5% | #8 |
| pptxslidesagents | 1157 | 45.3% | #7 |
| python-pptxslidesagents | 1152 | 43.3% | #8 |
| Web appsagents | 1181 | 45.4% | #18 |
| 3Dmodels | 1264 | 53.4% | #28 |
| ASCII artmodels | 1316 | 63.3% | #2 |
| Codemodels | 1296 | 56.8% | #15 |
| Data vizmodels | 1304 | 58.8% | #8 |
| Game devmodels | 1348 | 62.7% | #3 |
| SVGmodels | 1284 | 60% | #6 |
| UI componentsmodels | 1301 | 57.6% | #13 |
| Websitesmodels | 1289 | 55.9% | #19 |
Head-to-head preference voting. How we filter and rank
Supported parameters
- include_reasoning
- max_completion_tokens
- max_tokens
- reasoning
- response_format
- seed
- structured_outputs
- tool_choice
- tools
Call it
OpenAI-compatible: point your SDK at api.openkey.ai/v1 and use model openai/gpt-5.5.
curl https://api.openkey.ai/v1/chat/completions \
-H "Authorization: Bearer $OPENKEY_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "openai/gpt-5.5",
"messages": [{"role": "user", "content": "Hello"}]
}'import os
from openai import OpenAI
client = OpenAI(
base_url="https://api.openkey.ai/v1",
api_key=os.environ["OPENKEY_API_KEY"],
)
completion = client.chat.completions.create(
model="openai/gpt-5.5",
messages=[{"role": "user", "content": "Hello"}],
)
print(completion.choices[0].message.content)import OpenAI from "openai";
const client = new OpenAI({
baseURL: "https://api.openkey.ai/v1",
apiKey: process.env.OPENKEY_API_KEY,
});
const completion = await client.chat.completions.create({
model: "openai/gpt-5.5",
messages: [{ role: "user", content: "Hello" }],
});
console.log(completion.choices[0].message.content);Questions
- How much does GPT-5.5 cost via API?
- Through OpenKey, GPT-5.5 costs $5.15 per 1M input tokens and $30.90 per 1M output tokens. That is the provider price ($5.00 / $30.00) plus a flat 3% fee — nothing else.
- What is GPT-5.5's context window?
- GPT-5.5 accepts up to 1.1M tokens of context and returns up to 128K tokens per request.
- Is GPT-5.5 OpenAI-compatible?
- Yes. Send requests to OpenKey's /v1/chat/completions endpoint with model "openai/gpt-5.5" using any OpenAI SDK — only the base URL and API key change.
- What inputs does GPT-5.5 support?
- GPT-5.5 accepts file, image, text input and produces text output. Its knowledge cutoff is Dec 1, 2025.
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