gpt-oss-20b: model ids, price and cutoff

How to call it

4 ways to use gpt-oss-20b, with the model id each provider expects.

Providers, model ids, endpoints and docs for gpt-oss-20b
Provider	Model id	Endpoint	Docs
Hugging Face			huggingface.co
OpenAI API (docs)	`gpt-oss-20b`	`https://api.openai.com/v1/responses`	developers.openai.com
Azure OpenAI (Microsoft Foundry)	`gpt-oss-20b`		learn.microsoft.com
OpenRouter	`openai/gpt-oss-20b`		openrouter.ai

Pricing

Price not published.

No price source linked. Checked 29 September 2026.

Specs

Input: Text
Output: Text
Context window: 131,072 tokens
Max output: 131,072 tokens
Open weights: Yes
Licence: Apache-2.0
Training cutoff: June 2024
Released: 5 August 2025
Status: Current
Type: Reasoning model

What stands out

What its maker marketed at launch, and what people found later, each with its source.

Laptop-class open reasoning

21B total / 3.6B active MoE in MXFP4; runs in ~16GB memory.

Source: huggingface.co
Fine-tunable on consumer hardware

Apache 2.0 weights, fine-tunable locally; function calling and structured outputs.

Source: huggingface.co

Four assistants, one scale

gpt-oss-20b is added as a fifth row. Each row runs from what the model knows (graphite) through the months between its cutoff and its launch (hatched) to today (pink).

GPT-6 Astra 271 at launch, 1,863 today
Claude Opus 5.5 372 at launch, 1,795 today
Gemini 4 Hydrogen 1,863 at launch, 1,889 today
Grok 4.7 387 at launch, 1,829 today
gpt-oss-20b 51 at launch, 2,060 today

Show as a table

Model	Cutoff	Released	Missing at launch	Missing today
GPT-6 Astra	April 2026	3 September 2026	271	1,863
Claude Opus 5.5	June 2026	22 September 2026	372	1,795
Gemini 4 Hydrogen	March 2026	12 November 2026	1,863	1,889
Grok 4.7	May 2026	21 September 2026	387	1,829
gpt-oss-20b	June 2024	5 August 2025	51	2,060