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gpt-oss-120b

OpenAIReleased Aug 5, 2025

gpt-oss-120b is an open-weight, 117B-parameter Mixture-of-Experts (MoE) language model from OpenAI designed for high-reasoning, agentic, and general-purpose production use cases. It activates 5.1B parameters per forward pass and is optimized...

Try in playground
Context window
131K tokens
Max output
131K tokens
Input
text
Output
text
Tokenizer
GPT
Knowledge cutoff
Jun 30, 2024
Released
Aug 5, 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$0.030$0.0009$0.031
Output$0.150$0.0045$0.154

Benchmarks

Artificial Analysis

Intelligence index
23.8
Coding index
30.4
Agentic index
13.2

Design Arena

CategoryEloWin rateRank
3Dmodels97829.4%#90
Codemodels101333.4%#96
Data vizmodels104445.1%#86
Game devmodels105940.6%#84
UI componentsmodels98035.5%#91
Websitesmodels101132.5%#99

Head-to-head preference voting. How we filter and rank

Supported parameters

  • frequency_penalty
  • include_reasoning
  • logit_bias
  • logprobs
  • max_tokens
  • min_p
  • presence_penalty
  • reasoning
  • repetition_penalty
  • response_format
  • seed
  • stop
  • structured_outputs
  • temperature
  • tool_choice
  • tools
  • top_a
  • top_k
  • top_logprobs
  • top_p

Call it

OpenAI-compatible: point your SDK at api.openkey.ai/v1 and use model openai/gpt-oss-120b.

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-oss-120b",
    "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-oss-120b",
    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-oss-120b",
  messages: [{ role: "user", content: "Hello" }],
});
console.log(completion.choices[0].message.content);

Questions

How much does gpt-oss-120b cost via API?
Through OpenKey, gpt-oss-120b costs $0.031 per 1M input tokens and $0.154 per 1M output tokens. That is the provider price ($0.030 / $0.150) plus a flat 3% fee — nothing else.
What is gpt-oss-120b's context window?
gpt-oss-120b accepts up to 131K tokens of context and returns up to 131K tokens per request.
Is gpt-oss-120b OpenAI-compatible?
Yes. Send requests to OpenKey's /v1/chat/completions endpoint with model "openai/gpt-oss-120b" using any OpenAI SDK — only the base URL and API key change.
What inputs does gpt-oss-120b support?
gpt-oss-120b accepts text input and produces text output. Its knowledge cutoff is Jun 30, 2024.

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