exllamav3

Installation · Supported models · Examples · Quantization · Community

ExLlamaV3 is an inference library for running local LLMs on modern consumer GPUs, with flexible quantization and parallel inference.

• Quantization - EXL3, based on QTIP, plus 2–8 bit cache quantization.
• Parallel inference - Flexible tensor-parallel and expert-parallel inference for consumer hardware setups.
• CPU offloading - Allows large MoE models to run with limited GPU resources. AVX2 and AVX512 support.
• Generation - Continuous, dynamic batching, speculative decoding, multimodal support.
• Integrations - Broad HF model support, a Transformers plugin, and an OpenAI-compatible API via TabbyAPI.

[!TIP] Looking for a server? TabbyAPI is the official and recommended backend server. It provides an OpenAI-compatible API for local or remote inference, HF model downloading, embedding model support, and HF Jinja2 chat templates. Its startup script manages and installs prerequisites to help you get started.

Installation

Start by making sure you have the appropriate version of PyTorch installed (CUDA 12.4 or later) since the Torch dependency is not automatically handled by pip. Then pick a method below:

Prebuilt wheel · recommended

Pick a wheel from the releases page, then e.g.:

pip install https://github.com/turboderp-org/exllamav3/releases/download/v0.0.6/exllamav3-0.0.6+cu128.torch2.8.0-cp313-cp313-linux_x86_64.whl

Install from PyPI

pip install exllamav3

Note that the PyPI package does not contain a prebuilt extension and requires the CUDA toolkit and build prerequisites (i.e. VS Build Tools on Windows, gcc on Linux, python-dev headers etc.).

Build from source

exllamav3 declares a minimum torch version (>= 2.6.0) and CUDA version (>= 12.4), but beyond that the user is free to select a version of torch that is compatible with their environment.

torch can be installed in three ways (from least to most effort):

1. with uv, setting only --extra cuXXX installs torch automatically with the specified CUDA version, torch version is selected by uv from compatible versions in the specific index associated with the chosen CUDA version (options 1 and 2)
2. with uv, creating a thin project that depends on exllamav3[cuXXX] and pins a specific torch version — like (1) but torch is pinned in the thin project's pyproject.toml, see pinning a specific PyTorch version (optional) for details
3. Manually with uv pip or pip (options 3 and 4)

The flavor extras (--extra) are cu124, cu126, cu128, cu129, cu130, and cu132 — pick the one matching your installed CUDA build. Both uv sync and pip install . build the package in an isolated environment where your torch is not visible, so they install the extension sources and compile them at first import (JIT, a few minutes once per torch version). For a precompiled install run pip install --no-build-isolation . in an environment that already has torch, or use the release wheels. Selecting a flavor installs the matching CUDA build of torch.

Option 1 — Working in the cloned repo directly (uv sync):

git clone https://github.com/turboderp-org/exllamav3
cd exllamav3
# (Optional) switch to dev branch for latest in-progress features
git checkout dev

uv venv
uv sync --extra cu130
# add --extra examples and/or --extra eval for those extra dependencies

Option 2 — Using exllamav3 as a dependency from another project (uv add):

# `uv add` works inside an existing project (a directory with a pyproject.toml).
# `uv init` creates one if you're starting a new project, if integrating into
# an existing project skip `uv init`.
uv init my-project
cd my-project

# local checkout
uv add 'path/to/exllamav3[cu130]'               # non-editable
uv add 'path/to/exllamav3[cu130]' --editable    # editable

# straight from GitHub
uv add 'git+https://github.com/turboderp-org/exllamav3.git[cu130]'                 # default branch
uv add 'git+https://github.com/turboderp-org/exllamav3.git[cu130]' --branch dev    # specific branch

Option 3 — Bring your own torch and let uv pick the backend automatically:

uv venv            # or: uv venv --python-preference only-managed
source .venv/bin/activate
uv pip install torch --torch-backend=auto
uv pip install .

--torch-backend=auto inspects your system and installs the matching PyTorch CUDA build; see Automatic backend selection.

Option 4 — With pip:

On Windows, you also need the triton-windows package (declared as a dependency in pyproject.toml); the attention, cache and recurrent kernels are Triton and ExLlamaV3 does not import without it.

# install a CUDA-enabled torch first so it matches your setup, e.g.:
pip install torch --index-url https://download.pytorch.org/whl/cu128
pip install .

Pinning a specific PyTorch version (optional)

The flavor extra picks the index, but by default torch resolves to the latest version on that index that satisfies >=2.6.0. To pin a specific torch version while developing on exllamav3, create a "thin" project that consumes your local checkout as an editable install and declares the exact torch version itself. This keeps the pin out of the exllamav3 pyproject, so you can change the torch version freely without touching the repo.

my-exllamav3-dev/          # thin project (uv init)
├── pyproject.toml
└── src/                  # package sources (auto-generated)

In pyproject.toml:

[project]
name = "my-exllamav3-dev"
version = "0.1.0"
description = "Dev environment for exllamav3"
requires-python = ">=3.10.11"
dependencies = [
    "exllamav3[cu130]",   # select correct CUDA version
    "torch==2.13.0",      # pin the exact torch version you need
]

[tool.uv.sources]
exllamav3 = { path = "../exllamav3", editable = true }

Adjust ../exllamav3 to point at your local checkout, then a plain uv sync sets up an environment with the correct PyTorch index (routed via the cuXXX extra), the pinned version of torch from that index (as long as it exists), and an editable install of exllamav3 so code changes apply immediately. Switch CUDA flavors by changing the extra (exllamav3[cu124], exllamav3[cu128], …) and/or the torch pin in the thin project.

Or, if you're installing torch manually with uv pip install torch (e.g. as in Option 3 above), specify the version directly, e.g. uv pip install "torch==2.11.0" --torch-backend=auto.

After installing with one of the options above, you should be able to run the conversion, eval and example scripts from the main repo directory, e.g., uv run python convert.py -i ... or, for manual installations once the venv is active, python convert.py -i ...

Build environment variables

• MAX_JOBS: by default ninja may launch too many processes and run out of system memory for compilation. Set this to a reasonable value like 4 in that case.
• EXLLAMA_NOCOMPILE: set to install the library without compiling the C++/CUDA extension. Torch will build/load it at runtime instead.
• EXLLAMA_EXT_LINEINFO, EXLLAMA_EXT_COMPRESS: see doc/env_vars.md.

Examples

A number of example scripts are provided to showcase the features of the backend and generator. For instance, a versatile CLI chatbot:

python examples/chat.py -m <input_dir> -mode <prompt_mode>

# Wealth of options
python examples/chat.py -h

Architecture support

Model family	HF architecture	Multimodal	Notes
AFM	ArceeForCausalLM
AfMoE	AfmoeForCausalLM
Apertus	ApertursForCausalLM
Command-R etc.	CohereForCausalLM
Command-A, Command-R+ etc.	Cohere2ForCausalLM
DeciLM, Nemotron	DeciLMForCausalLM
Deepseek V3	DeepseekV3ForCausalLM
Deepseek V4	DeepseekV4ForCausalLM	✓
dots.llm1	Dots1ForCausalLM
ERNIE 4.5	Ernie4_5_ForCausalLMErnie4_5_MoeForCausalLM
EXAONE 4.0	Exaone4ForCausalLM
Gemma 2	Gemma2ForCausalLM
Gemma 3	Gemma3ForCausalLMGemma3ForConditionalGeneration	✓
Gemma 4	Gemma4ForConditionalGenerationGemma4UnifiedForConditionalGeneration	✓	E2B/E4B unsupported
GLM 4, GLM 4.6, etc.	Glm4ForCausalLMGlm4MoeForCausalLM

Always adding more, stay tuned.

Conversion

To convert a model to EXL3 format, use:

# Convert model
python convert.py -i <input_dir> -o <output_dir> -w <working_dir> -b <bitrate>

# Resume an interrupted quant job
python convert.py -w <working_dir> -r

# More options
python convert.py -h

The working directory is temporary storage for state checkpoints and for storing quantized tensors until the converted model can be compiled. It should have enough free space to store an entire copy of the output model.

See the conversion guide for more information, or the self-calibration guide.

EXL3 quantization

EXL3 quantization is a streamlined variant of QTIP from Cornell RelaxML. It aims to make SOTA quantization available to users on consumer hardware. The conversion process is designed to be simple and efficient and requires only an input model (in HF format) and a target bitrate. By computing Hessians on the fly and thanks to a fused Viterbi kernel, the quantizer can convert a model in a single step, taking a couple of minutes for smaller models, up to a few hours for larger ones (70B+) on a single high-end consumer GPU (see the conversion guide).

For more information, see the QTIP and QuIP# papers, as well as this excellent writeup on QTIP from together.ai.

Community

You are always welcome to join the ExLlama discord server ←🎮

🤗 Models on Hugging Face

Browse the EXL3 model collection for quantized models. Also shout out to the following lovely people:

• ArtusDev
• MikeRoz
• MetaphoricalCode
• Ready.Art
• isogen

Acknowledgements

This project owes its existence to a wonderful community of FOSS developers and some very generous supporters (🐈❤️!) The following projects in particular deserve a special mention:

• TabbyAPI
• PyTorch
• FlashAttention
• QTIP
• Transformers
• Marlin
• Flash Linear Attention (chunked linear-attention prefill kernels, vendored under exllamav3/vendor/fla)