OpenAI API exposes gpt-oss-20b through model ID gpt-oss-20b. Use the setup steps, sourced pricing, capabilities, and official provider links below to validate this route before deployment.
Last refreshed 2026-04-19. Next refresh: weekly.
Quick Start
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Code Examples
Install
pip install openaiAPI key
OPENAI_API_KEYModel ID
gpt-oss-20bUse the model slug directly, e.g. "gpt-4o" or "gpt-4.1-mini".
import os
from openai import OpenAI
client = OpenAI() # reads OPENAI_API_KEY from env
response = client.chat.completions.create(
model="gpt-oss-20b",
messages=[{"role": "user", "content": "Hello"}]
)
print(response.choices[0].message.content)Pricing on OpenAI API
Capabilities
JSON / Tool useStructured Outputs
About gpt-oss-20b
OpenAI open-weight model with 20 billion parameters. Lightweight, efficient text-only model with reasoning and function calling. Free for self-hosting. Released August 5, 2025.
Model Specs
Released2025-08-05
Parameters20B
Context131k
ArchitectureDecoder Only
Knowledge cutoff2025-08