gpt-oss-20b

reasoningapache-2.020B

`gpt-oss-20b` is our medium-sized open-weight model for low latency, local, or specialized use-cases (21B parameters with 3.6B active parameters).

Intelligence
Reasoning
Speed
Context
131K
Max output
131K

Capabilities

Reasoning & Interaction
Reasoning
Tool Calling
Output Control
Structured Output
JSON Mode
Infrastructure
Streaming
Batch Processing

Details

Provider OpenAI
Creator openai
Familygpt-oss
Licenseapache-2.0
Statusactive
Typereasoning
Input modalitiestext
Output modalitiestext
Open weightYes
Parameters20B
Architecture—
Context window131K tokens
Max input—
Max output131K tokens
Reasoning tokensYes
Knowledge cutoff
Release date—
Sourceofficial

Tools

Function Callingfunction_calling
Call external functions and APIs
Code Interpretercode_interpreter
Execute code in a sandbox
MCPmcp
Connect to Model Context Protocol servers
Web Searchweb_search
Search the web for information

Endpoints

ResponsesPOST
Stateful multi-turn conversationshttps://api.openai.com/v1/responses
BatchPOST
Async batch processing at lower costhttps://api.openai.com/v1/batches

Family Comparison: gpt-oss

ModelContextMax out
gpt-oss-120b131K131K
gpt-oss-20b131K131K

API

GET/v1/models/openai/gpt-oss-20b