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OpenKey

GPT-5 Nano

OpenAIReleased Aug 7, 2025

GPT-5-Nano is the smallest and fastest variant in the GPT-5 system, optimized for developer tools, rapid interactions, and ultra-low latency environments. While limited in reasoning depth compared to its larger...

Try in playground
Context window
400K tokens
Input
text, image, file
Output
text
Tokenizer
GPT
Knowledge cutoff
May 31, 2024
Released
Aug 7, 2025
Reasoning
always on

Pricing

Per 1M tokens. The provider price and our flat 3% fee are separate columns — what you pay is their sum.

Per 1M tokensProvider+ 3% feeYou pay
Input$0.050$0.0015$0.052
Output$0.400$0.012$0.412
Cache read$0.010$0.0003$0.010

Benchmarks

Design Arena

CategoryEloWin rateRank
3Dmodels104136.1%#86
Codemodels113448.1%#74
Data vizmodels110446.7%#76
Game devmodels111146.6%#76
UI componentsmodels112252%#70
Websitesmodels114448.9%#74

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-nano.

Code sample language
curl https://api.openkey.ai/v1/chat/completions \
  -H "Authorization: Bearer $OPENKEY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-5-nano",
    "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-nano",
    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-nano",
  messages: [{ role: "user", content: "Hello" }],
});
console.log(completion.choices[0].message.content);

Questions

How much does GPT-5 Nano cost via API?
Through OpenKey, GPT-5 Nano costs $0.052 per 1M input tokens and $0.412 per 1M output tokens. That is the provider price ($0.050 / $0.400) plus a flat 3% fee — nothing else.
What is GPT-5 Nano's context window?
GPT-5 Nano accepts up to 400K tokens of context.
Is GPT-5 Nano OpenAI-compatible?
Yes. Send requests to OpenKey's /v1/chat/completions endpoint with model "openai/gpt-5-nano" using any OpenAI SDK — only the base URL and API key change.
What inputs does GPT-5 Nano support?
GPT-5 Nano accepts text, image, file input and produces text output. Its knowledge cutoff is May 31, 2024.

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