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GPT-OSS 20B

GPT-OSS
by OpenAI

Smaller Mixture of Experts (MoE) text-only LLM for efficient AI reasoning and math.

Try in Chat
Free EndpointDownloadableAug 5, 2025open license18M API calls / 30d

Specifications

Context Length
131K
131,072 tokens
Input Price
Free
per 1M tokens
Output Price
Free
per 1M tokens
Modalities
1
text→text

Capabilities

text generationchatreasoningcode

Tags

reasoningMoEmathsmall-model

API Usage

1Router is fully OpenAI-compatible. Just set the base URL and use this model ID:

openai/gpt-oss-20b
cURL
curl https://api.1router.com/v1/chat/completions \
  -H "Authorization: Bearer $ROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-oss-20b",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'