GPT OSS 20B is an open-weight language model by OpenAI optimized for efficient, local, and specialized use cases with strong reasoning and coding capabilities. It offers a balance of high performance and low latency, making it suitable for edge devices and applications needing rapid iteration or lower compute requirements. Designed for agentic workflows, it supports chain-of-thought reasoning, function calling, and Python code execution, with customizable reasoning effort and structured output capabilities.
vs GPT OSS 120B: GPT OSS 20B operates efficiently on limited hardware with 16GB memory, making it well-suited for local and rapid deployment with solid reasoning and coding capabilities, whereas GPT OSS 120B offers significantly larger capacity (120B parameters), delivers higher accuracy, and is designed for large-scale, high-compute tasks.
vs OpenAI o3-mini: GPT OSS 20B demonstrates comparable performance to the o3-mini model, with the added advantage of open-weight access and flexible configuration, benefiting researchers and developers who require transparency and customization.
vs GLM-4.5: GLM-4.5 outperforms GPT OSS 20B in practical coding challenges and advanced tool integration, but GPT OSS 20B remains competitive in general reasoning tasks and is easier to deploy on hardware with limited resources.
Measured on the AI/ML API gateway across live traffic. Figures are medians unless stated. Last updated 2026-10-12.
import requests r = requests.post( "https://api.aimlapi.com/v1/chat/completions", headers={"Authorization": "Bearer " + AIMLAPI_KEY}, json={ "model": "openai/gpt-oss-20b", "messages": [ { "role": "user", "content": "Hello!" } ] }, ) print(r.json())
const r = await fetch("https://api.aimlapi.com/v1/chat/completions", { method: "POST", headers: { Authorization: `Bearer ${process.env.AIMLAPI_KEY}`, "Content-Type": "application/json", }, body: JSON.stringify({ "model": "openai/gpt-oss-20b", "messages": [ { "role": "user", "content": "Hello!" } ] }), }); console.log(await r.json());
curl -X POST https://api.aimlapi.com/v1/chat/completions \ -H "Authorization: Bearer $AIMLAPI_KEY" \ -H "Content-Type: application/json" \ -d '{"model":"openai/gpt-oss-20b","messages":[{"role":"user","content":"Hello!"}]}'
OpenAI-compatible — swap the base URL and it works with your existing SDK.
| Type | Price |
|---|---|
| Input | |
| Output | |
| Cached input |
| Benchmark | Score | What it measures | Source | Retrieved |
|---|---|---|---|---|
| Humanity's Last Exam | 10.9% | Expert-level questions across many domains | Source | July 13, 2026 |
| GPQA Diamond | 71.5% | Google-proof graduate science questions (hardest subset) | Source | July 13, 2026 |
| AIME 2025 | 91.7% | Competition mathematics (AIME), 2025 | Source | July 13, 2026 |
| Intelligence | 10 | Composite score across standardised reasoning, knowledge and problem-solving evaluations, measured independently by Artificial Analysis | Source | September 12, 2026 |
| Math | 62.3 | Composite score across standardised mathematics evaluations, measured independently by Artificial Analysis | Source | September 12, 2026 |
| Model | Input | Output | Context | Best for |
|---|---|---|---|---|
GPT OSS 20B This page | Reasoning + agents | |||
| Reasoning + agents | ||||
| Balanced coding + agents | ||||
| Long-context, multimodal & agentic workflows | ||||
| Reasoning + agents |
GPT OSS 20B has a 131,000 tokens context window and can return up to 131,072 tokens.
GPT OSS 20B takes text as input and returns text.
Use openai/gpt-oss-20b as the model id. Requests go to https://api.aimlapi.com/v1/chat/completions.
GPT OSS 20B became available on September 9, 2025.
GPT OSS 20B is priced at input $0.103155 / 1M tokens, output $0.41262 / 1M tokens, cached input $0.0515775 / 1M tokens.
Yes, GPT OSS 20B can stream responses as they are generated.
GPT OSS 20B was built by OpenAI.
