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gpt-oss-20b (free)

OpenAIReleased Aug 5, 2025Free

gpt-oss-20b is an open-weight 21B parameter model released by OpenAI under the Apache 2.0 license. It uses a Mixture-of-Experts (MoE) architecture with 3.6B active parameters per forward pass, optimized for...

Try in playground
Context window
131K tokens
Max output
33K 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
InputFreeFree
OutputFreeFree

Benchmarks

Artificial Analysis

Intelligence index
14.9
Coding index
20.7
Agentic index
3.1

Design Arena

CategoryEloWin rateRank
Data vizmodels97839.7%#92
Websitesmodels89527.9%#107

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

Supported parameters

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

Call it

OpenAI-compatible: point your SDK at api.openkey.ai/v1 and use model openai/gpt-oss-20b:free.

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-20b:free",
    "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-20b:free",
    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-20b:free",
  messages: [{ role: "user", content: "Hello" }],
});
console.log(completion.choices[0].message.content);

Questions

How much does gpt-oss-20b (free) cost via API?
gpt-oss-20b (free) is free through OpenKey while OpenAI offers it at no charge. No fee applies to free models.
What is gpt-oss-20b (free)'s context window?
gpt-oss-20b (free) accepts up to 131K tokens of context and returns up to 33K tokens per request.
Is gpt-oss-20b (free) OpenAI-compatible?
Yes. Send requests to OpenKey's /v1/chat/completions endpoint with model "openai/gpt-oss-20b:free" using any OpenAI SDK — only the base URL and API key change.
What inputs does gpt-oss-20b (free) support?
gpt-oss-20b (free) accepts text input and produces text output. Its knowledge cutoff is Jun 30, 2024.

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