System Duo
System Duo is AI that decides in a blink and reasons in depth. vLLM Semantic Router works with any model, open or closed.. It is ranked #196 on the AI Radar, in AI infra & evals, first seen 21 h ago and shared in 2 posts (10.8k views).
System Duo · Thinking, fast and slow. Skip to content , System Duo home Menu System Duo Thinking, fast and slow . AI that decides in a blink and reasons in depth. Get your free API key Creating your key Key created Install for DeepSeek Harness Research use only · Terms · Privacy Creating a key here needs JavaScript. Create one from a terminal . Your API key Manage keys (opens in a new tab) Copy Copied Save it now: it is shown only once. Your first calls System One System Two curl -s https://app.vllm-sr.ai/v1/systemone \ -H "Authorization: Bearer $VLLM_SR_API_KEY" \ -H "Content-Type: application/json" \ -d '{"model": "vllm-sr/d3-ultra",…
What people said about System Duo on X
One router, two minds 🧠⚡ Huge work from @XunzhuoLiu and the vLLM Semantic Router team on System Duo — fast decision models handle the blink-of-an-eye calls (triage, guard, verify, check), while the router sends deep reasoning to the right model only when it matters. All open source, all running on vLLM →…
— @vllm_project, 18 h ago · 67 likes · see the post
𝗠𝗮𝗸𝗲 𝘆𝗼𝘂𝗿 𝗮𝗴𝗲𝗻𝘁 𝘁𝗵𝗶𝗻𝗸 𝗳𝗮𝘀𝘁 𝗮𝗻𝗱 𝘀𝗹𝗼𝘄. System One decides in a blink. System Two reasons in depth. 𝗢𝗻𝗲 𝗿𝗼𝘂𝘁𝗲𝗿. 𝗧𝘄𝗼 𝗺𝗶𝗻𝗱𝘀. 𝗜𝗻𝘁𝗿𝗼𝗱𝘂𝗰𝗶𝗻𝗴 𝗦𝘆𝘀𝘁𝗲𝗺 𝗗𝘂𝗼 → https://app.vllm-sr.ai #Jev #SystemOne #SystemTwo #OpenSource
— @XunzhuoLiu, 21 h ago · 33 likes · see the post
Alternatives to System Duo
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- OrcaRouter — Claim yours
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- LongCatAI — Take a closer look at what it can do
- Nous Portal — Great time to try it out
- together.ai — Together AI
System Duo in numbers
- Rank on the AI Radar: #196 of 10425
- Shared in 2 posts by 2 accounts: @vllm_project, @XunzhuoLiu
- 10.8k views on those posts
- First seen 21 h ago, last shared 18 h ago
- Pricing seen by AGK Intelligence: open source
- Market: AI infra & evals
FAQ
What is System Duo?
AI that decides in a blink and reasons in depth. vLLM Semantic Router works with any model, open or closed. It was first shared on X 21 h ago and is ranked #196 on the AI Radar.
Is System Duo free?
It is open source.
Who shared System Duo?
2 accounts on X, including @vllm_project, @XunzhuoLiu, in 2 posts totalling 10.8k views.
Every post is read and classified by AGK Intelligence: what it is, which market it belongs to, and whether the link is a real tool. 65.3k posts from 5k X accounts over the last 14 days, 10.4k tools, 19 markets. New posts are collected several times an hour and the full ranking is recomputed every hour — last update 2026-11-06 17:44 UTC. Full method.