gpt-oss-20b

OpenAI· released 5 Aug 2025

openai/gpt-oss-20b

Input / 1M tokens: $0.018
Output / 1M tokens: $0.09

Context window131K tokens

Longest answer: 33K tokens

reads textopen weightstool callingreasoning

About

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...

Details

Lab: OpenAIopenrouter.ai · 3 Oct 2026
Context: 131Kopenrouter.ai · 3 Oct 2026
Input price: $0.018 / 1Mopenrouter.ai · 3 Oct 2026
Output price: $0.09 / 1Mopenrouter.ai · 3 Oct 2026
Max output: 32,768 tokensopenrouter.ai · 3 Oct 2026
Inputs: textopenrouter.ai · 3 Oct 2026
Open weights: Yesopenrouter.ai · 3 Oct 2026

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Sources

openrouter.ai/openai/gpt-oss-20b· checked 3 Oct 2026