gpt-oss-20b

Name: OpenAI: gpt-oss-20b
Brand: openai
SKU: openai/gpt-oss-20b
Price: 0.033 USD
Availability: InStock

openai/gpt-oss-20b

gpt-oss-20b is an open-weight 21B parameter model released by OpenAI under the Apache 2.0 license.

$0.033 in · $0.143 out per 1M tokens131k contextAug 5, 2025

less than 1/100 of a cent a message

A typical message: about 500 tokens you send and 500 it writes.

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Also:batch

Spec sheet

Published facts from the catalog, billed prices and what we measured here. Anything not measured says so.

Price, billed here

Input, per 1M tokens: $0.033provider $0.03
Output, per 1M tokens: $0.143provider $0.13
Cached input, per 1M: $0.033provider $0.03
Margin: +10%

Context and formats

Context window: 131,072 tokens
Longest answer: 117,964 tokens
Reads: text
Makes: text
First listed: 2025-08-05

Measured here, last 7 days

First token, median: not measured
Answered without error: not measured

Tools and JSON

Tool calling: declaredthe provider's claim, not yet measured here
JSON output: declaredthe provider's claim, not yet measured here

Price and latency history as JSON: GET /api/planet/history?id=openai/gpt-oss-20b.

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...

In OpenAI's words.

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Measured here

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Call it

Use one OpenAI compatible endpoint, this model's id and an am_live_ key from the dashboard. You can also try it in chat first with no key.

curl https://useantimatter.com/v1/chat/completions \
  -H "Authorization: Bearer $ANTIMATTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "openai/gpt-oss-20b", "messages": [{"role": "user", "content": "Hello"}]}'

Everything else is in the docs.

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A badge showing this model's live price per million tokens, as billed here, for a README or a site. It links back to this page.

<a href="https://useantimatter.com/planet/openai/gpt-oss-20b"><img src="https://useantimatter.com/api/badge/price?id=openai%2Fgpt-oss-20b" alt="gpt-oss-20b price on Antimatter" height="28"></a>

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