About
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.
Pricing
| Input | $7.00 | per 1M prompt tokens |
|---|---|---|
| Output | $42.00 | per 1M generated tokens, reasoning included |
| Cached input | $0.70 | per 1M tokens read back from the prompt cache |
| Input over 272K | $14.00 | the whole prompt is billed at this rate once it passes the threshold |
| Output over 272K | $63.00 | applies to replies to those prompts |
| Web search | $0.014 | per request that uses the provider’s built-in search |
What a request costs
| Typical request | Each | Per 1,000 |
|---|---|---|
| Short chat reply1,500 in · 400 out | $0.027 | $27.30 |
| Question over a long document40,000 in · 800 out | $0.314 | $313.60 |
| Agent tool step20,000 in · 1,200 out | $0.190 | $190.40 |
| Very long prompt (over 272K)340,000 in · 1,500 out | $4.85 | $4,855 |
At the developer-API rate, before any provider promotion or prompt-cache saving. In the app, the model picker shows what a message costs on your plan before you send it.
Benchmarks
Head-to-head rankings
- #6SlidesAgent arenaElo 115044% wins
- #14Game devAgent arenaElo 117952% wins
- #14ASCII artModel arenaElo 125858% wins
- #16SVGModel arenaElo 123355% wins
- #18Godot gamesAgent arenaElo 117352% wins
- #19Android appsAgent arenaElo 117851% wins
- #20Game devModel arenaElo 129657% wins
- #28Data vizModel arenaElo 126556% wins
- #29Full stackAgent arenaElo 108943% wins
- #30Mobile appsAgent arenaElo 113950% wins
Scores from Artificial Analysis; bars are scaled to the best model on our list. Rankings from Design Arena head-to-head votes. Published by OpenRouter alongside its catalogue.
Call it from code
OpenAI-compatible: point any OpenAI SDK at https://api.privateer.pro/v1 and set
model. Keys are created in the app under Settings.
cURL
curl https://api.privateer.pro/v1/chat/completions \
-H "Authorization: Bearer $PRIVATEER_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "openai/gpt-5.5",
"messages": [{ "role": "user", "content": "Hello" }],
"reasoning": { "effort": "medium" }
}'Python
import os
from openai import OpenAI
client = OpenAI(
base_url="https://api.privateer.pro/v1",
api_key=os.environ["PRIVATEER_API_KEY"],
)
reply = client.chat.completions.create(
model="openai/gpt-5.5",
messages=[{"role": "user", "content": "Hello"}],
)
print(reply.choices[0].message.content)JavaScript
import OpenAI from "openai";
const client = new OpenAI({
baseURL: "https://api.privateer.pro/v1",
apiKey: process.env.PRIVATEER_API_KEY,
});
const reply = await client.chat.completions.create({
model: "openai/gpt-5.5",
messages: [{ role: "user", content: "Hello" }],
});
console.log(reply.choices[0].message.content);Parameters this model accepts
include_reasoningmax_completion_tokensmax_tokensreasoningreasoning_effortresponse_formatseedstructured_outputstool_choicetoolsverbosity