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NVIDIA

Nemotron 3 Ultra (free)

nvidia/nemotron-3-ultra-550b-a55b:free

NVIDIA Nemotron 3 Ultra is an open frontier-reasoning and orchestration model from NVIDIA, with 55B active parameters out of 550B total (MoE).

Free in · Free out per 1M tokens1M contextJun 4, 2026

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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
Output, per 1M tokens
$0
Margin
none

Context and formats

Context window
1,000,000 tokens
Longest answer
65,536 tokens
Reads
text
Makes
text
First listed
2026-06-04

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
not declared

Price and latency history as JSON: GET /api/planet/history?id=nvidia/nemotron-3-ultra-550b-a55b:free.

About

NVIDIA Nemotron 3 Ultra is an open frontier-reasoning and orchestration model from NVIDIA, with 55B active parameters out of 550B total (MoE). Built on a hybrid Transformer-Mamba mixture-of-experts architecture, it...

In NVIDIA's words.

Try it here

The answer appears here.

Measured here

Call it

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curl https://useantimatter.com/v1/chat/completions \
  -H "Authorization: Bearer $ANTIMATTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "nvidia/nemotron-3-ultra-550b-a55b:free", "messages": [{"role": "user", "content": "Hello"}]}'

Everything else is in the docs.

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Nemotron 3 Ultra (free) price on Antimatter
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