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Specifications
Specifications and pricing as served by Composite
Model ID
nvidia/nemotron-3-ultra-550b-a55b-reasoning
Provider
DeepInfra
Context window
262,144 tokens
Accepts
text
Returns
text
Input price
$0.500 per million tokens
Output price
$2.20 per million tokens
Prompt caching
Supported — cached input is billed at the provider's cache rate, on credits and plans alike
Thinking
Optional - see "NVIDIA: Nemotron 3 Ultra (Reasoning) (Reasoning)" in the catalog to turn it on by default
Moderated
No
Cost on a monthly plan
About 5.0 plan credits per typical call (8k in, 1k out)
Routing endpoints
1
Use NVIDIA: Nemotron 3 Ultra (Reasoning) in JanitorAI or SillyTavern
Make a Composite API key and type nvidia/nemotron-3-ultra-550b-a55b-reasoning as the model name. JanitorAI takes the full URL https://composite.lucidity.sh/v1/chat/completions; SillyTavern, ChubAI, Agnai and RisuAI take https://composite.lucidity.sh/v1. It runs on credits, a plan, or your own provider key.
This model has not carried enough traffic on Composite yet to publish a success rate, a latency figure or a traffic rank. The numbers appear here once it has.
Pricing
$0.500 per million tokens input · $2.20 per million tokens output
Credits pay the provider’s price plus 25%; cache hits cost less.
On a monthly plan, a typical call (8k tokens in, 1k out) uses about 5.0 plan credits, at the provider's own price.
Provider
DeepInfra
Roleplay fit
Nemotron models are tuned by NVIDIA for instruction-following and tool use, and tend to behave predictably in structured prompts.
Context behavior
With a 262,144-token context window, it can hold a long-running roleplay or a full lorebook in memory without losing earlier plot details, so it suits multi-session campaigns and character cards with heavy backstory.
Cost for regular use
It sits in the mid-range on price, a reasonable pick for regular roleplay use without going for the cheapest option available.
From the provider
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...