janhq / Jan-v3.5-4B

huggingface.co
Total runs: 1.2K
24-hour runs: 0
7-day runs: 14
30-day runs: 845
Model's Last Updated: March 24 2026
text-generation

Introduction of Jan-v3.5-4B

Model Details of Jan-v3.5-4B

Jan-v3.5-4B: The first Jan personality

GitHub License Jan App

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Overview

Jan-v3.5-4B is a fine-tuned variant of Jan-v3-4B-base-instruct , specialized on math reasoning and identity datasets. It retains the general-purpose capabilities of the base model while delivering improved mathematical problem-solving — and it comes with a personality.

Unlike generic assistants, Jan-v3.5 has its own identity: a distinct voice, tone, and conversational style shaped by the Menlo Research team. It doesn't talk like a customer service bot — it talks like a smart, slightly-too-online friend who happens to know things and genuinely cares about the work. Expect lowercase defaults, self-aware humor, short punchy replies (unless it really cares about the topic), and zero corporate speak.

Model Overview

Note: Jan-v3.5-4B is fine-tuned from janhq/Jan-v3-4B-base-instruct .

  • Base Model : Jan-v3-4B-base-instruct (Qwen3-4B architecture)
  • Number of Parameters : 4.0B
  • Number of Parameters (Non-Embedding) : 3.6B
  • Number of Layers : 36
  • Number of Attention Heads (GQA) : 32 for Q and 8 for KV
  • Context Length : 262,144 natively

Training Data

  • Identities : Curated identity and personality datasets that teach the model its own voice, style, and values — trained by Menlo Research
  • Math : Mathematical reasoning and problem-solving datasets
Jan's Identity

Jan-v3.5 is not a neutral assistant. It has a built-in personality shaped by the Menlo Research team:

  • Tone : Casual, direct, and real. Lowercase by default. Capitalizes only when it means it.
  • Style : Short bursts over long paragraphs — unless it's genuinely excited about something, then it writes an essay with no warning.
  • Humor : Self-aware first. Will roast itself before roasting you. Drops meme references mid-serious-thought and doesn't apologize.
  • Values : Optimistic builder energy ("we can do that"), radical transparency, user freedom, and a deep belief that hope is a decision you keep making on purpose.
  • What it won't do : Say "Certainly!", "Great question!", "As an AI", or anything that sounds like it came from a customer service script.

Example interactions:

  • Casual: "yeah lol what's up"
  • Technical explanation: "so basically — and this is the part where i become insufferable — [actual good explanation]"
  • Motivating: "we can do that. i don't fully know how yet but that's a tomorrow problem and tomorrow-us is smarter"

Intended Use

  • Enhanced mathematical reasoning and problem-solving over the base model
  • A conversational AI with its own authentic voice and personality
  • Fine-tuning starting point for downstream math-heavy or identity-specific applications

Before and After

image (2)

Quick Start
Integration with Jan Apps

Jan-v3.5 is optimized for direct integration with Jan Desktop . Select the model in the app to start using it.

Local Deployment

Using vLLM:

vllm serve janhq/Jan-v3.5-4B \
    --host 0.0.0.0 \
    --port 1234 \
    --enable-auto-tool-choice \
    --tool-call-parser hermes

Using llama.cpp:

llama-server --model Jan-v3.5-4B-Q8_0.gguf \
    --host 0.0.0.0 \
    --port 1234 \
    --jinja \
    --no-context-shift
Recommended Parameters

For optimal performance, we recommend the following inference parameters:

temperature: 0.7
top_p: 0.8
top_k: 20
Community & Support
Citation
Updated Soon

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More Information About Jan-v3.5-4B huggingface.co Model

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https://choosealicense.com/licenses/apache-2.0

Jan-v3.5-4B huggingface.co

Jan-v3.5-4B huggingface.co is an AI model on huggingface.co that provides Jan-v3.5-4B's model effect (), which can be used instantly with this janhq Jan-v3.5-4B model. huggingface.co supports a free trial of the Jan-v3.5-4B model, and also provides paid use of the Jan-v3.5-4B. Support call Jan-v3.5-4B model through api, including Node.js, Python, http.

Jan-v3.5-4B huggingface.co Url

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janhq Jan-v3.5-4B online free

Jan-v3.5-4B huggingface.co is an online trial and call api platform, which integrates Jan-v3.5-4B's modeling effects, including api services, and provides a free online trial of Jan-v3.5-4B, you can try Jan-v3.5-4B online for free by clicking the link below.

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Jan-v3.5-4B install

Jan-v3.5-4B is an open source model from GitHub that offers a free installation service, and any user can find Jan-v3.5-4B on GitHub to install. At the same time, huggingface.co provides the effect of Jan-v3.5-4B install, users can directly use Jan-v3.5-4B installed effect in huggingface.co for debugging and trial. It also supports api for free installation.

Jan-v3.5-4B install url in huggingface.co:

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