gpt-oss-20b

OpenAI · Released August 2025 · Knowledge cutoff June 2024

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

It is part of OpenAI's GPT family, where GPT-6 Astra leads, GPT-6 Sol and GPT-6 Luna cover the capability and speed tiers below it, the GPT-5.6 generation sits behind them, and Pro servings trade speed for deeper computation.

Facts and pricing

Provider

OpenAI

Context window

131K tokens

Input price

0.22 credits / 1M tokens ($0.018 raw)

Output price

1.1 credits / 1M tokens ($0.090 raw)

Vision (image input)

No

Tool calling

Yes

Extended reasoning

No

Credits are what Zeplik bills: 1 credit = $0.10, computed from the raw provider rate with a 1.20x margin. Raw prices shown per 1M tokens.

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What gpt-oss-20b is best for

• Balanced everyday work: writing, questions, brainstorming and summarization
• Tool use and agents: reliably calls functions, so it can search, run skills and drive workflows

Example prompts

Prompts that suit a general purpose model like gpt-oss-20b:

• Help me outline a talk about what I learned this year
• Compare these two paragraphs and tell me which is clearer and why
• Draft a polite reply declining this invitation
• Explain this concept with a concrete everyday analogy

OpenAI family

All 71 OpenAI models

Model comparisons

• Claude Opus 5.5 vs GPT-6 Astra
• Claude Opus 5.5 vs GPT-6 Sol
• GPT-6 Sol vs GPT-5.6 Sol
• GPT-6 Sol vs GPT-6 Astra

Frequently asked questions

What is gpt-oss-20b?

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

How much does gpt-oss-20b cost on Zeplik?

Input tokens cost 0.22 credits per million and output tokens 1.1 credits per million (1 credit = $0.10; the raw provider rates are $0.018 and $0.090 per million). New accounts start with free credits.

How long can a conversation with gpt-oss-20b be?

gpt-oss-20b has a 131K-token context window (131,072 tokens), which covers the conversation plus any documents you attach.

Does gpt-oss-20b support images and tools?

gpt-oss-20b is text-only and supports tool calling.

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