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# Environment variables

`huggingface_hub` can be configured using environment variables.

If you are unfamiliar with environment variable, here are generic articles about them
[on macOS and Linux](https://linuxize.com/post/how-to-set-and-list-environment-variables-in-linux/)
and on [Windows](https://phoenixnap.com/kb/windows-set-environment-variable).

This page will guide you through all environment variables specific to `huggingface_hub`
and their meaning.

> [!TIP]
> All environment variables are read at import time of `huggingface_hub`. Any modification
> made afterwards will not be taken into account. Make sure to set your environment variables
> before importing `huggingface_hub`.

## Generic

### HF_INFERENCE_ENDPOINT

To configure the inference api base url. You might want to set this variable if your organization
is pointing at an API Gateway rather than directly at the inference api.

Defaults to `"https://api-inference.huggingface.co"`.

### HF_HOME

To configure where `huggingface_hub` will locally store data. In particular, your token
and the cache will be stored in this folder.

Defaults to `"~/.cache/huggingface"` unless [XDG_CACHE_HOME](#xdgcachehome) is set.

### HF_HUB_CACHE

To configure where repositories from the Hub will be cached locally (models, datasets and
spaces).

Defaults to `"$HF_HOME/hub"` (e.g. `"~/.cache/huggingface/hub"` by default).

### HF_XET_CACHE

To configure where Xet chunks (byte ranges from files managed by Xet backend) are cached locally.

Defaults to `"$HF_HOME/xet"` (e.g. `"~/.cache/huggingface/xet"` by default).

### HF_ASSETS_CACHE

To configure where [assets](../guides/manage-cache#caching-assets) created by downstream libraries
will be cached locally. Those assets can be preprocessed data, files downloaded from GitHub,
logs,...

Defaults to `"$HF_HOME/assets"` (e.g. `"~/.cache/huggingface/assets"` by default).

### HF_TOKEN

To configure the User Access Token to authenticate to the Hub. If set, this value will
overwrite the token stored on the machine (in either `$HF_TOKEN_PATH` or `"$HF_HOME/token"` if the former is not set).

For more details about authentication, check out [this section](../quick-start#authentication).

### HF_TOKEN_PATH

To configure where `huggingface_hub` should store the User Access Token. Defaults to `"$HF_HOME/token"` (e.g. `~/.cache/huggingface/token` by default).


### HF_HUB_VERBOSITY

Set the verbosity level of the `huggingface_hub`'s logger. Must be one of
`{"debug", "info", "warning", "error", "critical"}`.

Defaults to `"warning"`.

For more details, see [logging reference](../package_reference/utilities#huggingface_hub.utils.logging.get_verbosity).

### HF_HUB_ETAG_TIMEOUT

Integer value to define the number of seconds to wait for server response when fetching the latest metadata from a repo before downloading a file. If the request times out, `huggingface_hub` will default to the locally cached files. Setting a lower value speeds up the workflow for machines with a slow connection that have already cached files. A higher value guarantees the metadata call to succeed in more cases. Default to 10s.

### HF_HUB_DOWNLOAD_TIMEOUT

Integer value to define the number of seconds to wait for server response when downloading a file. If the request times out, a TimeoutError is raised. Setting a higher value is beneficial on machine with a slow connection. A smaller value makes the process fail quicker in case of complete network outage. Default to 10s.

## Xet 

### Other Xet environment variables
* [`HF_HUB_DISABLE_XET`](../package_reference/environment_variables#hfhubdisablexet)
* [`HF_XET_CACHE`](../package_reference/environment_variables#hfxetcache)
* [`HF_XET_HIGH_PERFORMANCE`](../package_reference/environment_variables#hfxethighperformance)
* [`HF_XET_RECONSTRUCT_WRITE_SEQUENTIALLY`](../package_reference/environment_variables#hfxetreconstructwritesequentially)

### HF_XET_CHUNK_CACHE_SIZE_BYTES

To set the size of the Xet chunk cache locally. By default, the chunk cache is disabled. The chunk cache can be beneficial if you are generating new revisions to existing models or datasets as this is used to cache terms/chunks that are fetched from S3. A larger cache can better take advantage of deduplication across repos & files. To enable the chunk cache set the environment variable to a large number (10GB) or greater. However, in most cases when downloading or uploading new data, disabling the chunk cache will have better performance, which is why it is disabled by default.

Defaults to `0` (0 bytes, means chunk cache is disabled).

### HF_XET_SHARD_CACHE_SIZE_LIMIT

To set the size of the Xet shard cache locally. Increasing this will improve upload efficiency as chunks referenced in cached shard files are not re-uploaded. Note that the default soft limit is likely sufficient for most workloads. 

Defaults to `16000000000` (16GB).

### HF_XET_NUM_CONCURRENT_RANGE_GETS

To set the number of concurrent terms (range of bytes from within a xorb, often called a chunk) downloaded from S3 per file. Increasing this will help with the speed of downloading a file if there is network bandwidth available. 

Defaults to `16`.

## Boolean values

The following environment variables expect a boolean value. The variable will be considered
as `True` if its value is one of `{"1", "ON", "YES", "TRUE"}` (case-insensitive). Any other value
(or undefined) will be considered as `False`.

### HF_DEBUG

If set, the log level for the `huggingface_hub` logger is set to DEBUG. Additionally, all requests made by HF libraries will be logged as equivalent cURL commands for easier debugging and reproducibility.

### HF_HUB_OFFLINE

If set, no HTTP calls will be made to the Hugging Face Hub. If you try to download files, only the cached files will be accessed. If no cache file is detected, an error is raised This is useful in case your network is slow and you don't care about having the latest version of a file.

If `HF_HUB_OFFLINE=1` is set as environment variable and you call any method of [`HfApi`], an [`~huggingface_hub.errors.OfflineModeIsEnabled`] exception will be raised.

**Note:** even if the latest version of a file is cached, calling `hf_hub_download` still triggers a HTTP request to check that a new version is not available. Setting `HF_HUB_OFFLINE=1` will skip this call which speeds up your loading time.

If you want to check if offline mode is enabled or not, you can use the [`is_offline_mode`] helper.

### HF_HUB_DISABLE_IMPLICIT_TOKEN

Authentication is not mandatory for every request to the Hub. For instance, requesting
details about `"gpt2"` model does not require to be authenticated. However, if a user is
[logged in](../package_reference/login), the default behavior will be to always send the token
in order to ease user experience (never get a HTTP 401 Unauthorized) when accessing private or gated repositories. For privacy, you can
disable this behavior by setting `HF_HUB_DISABLE_IMPLICIT_TOKEN=1`. In this case,
the token will be sent only for "write-access" calls (example: create a commit).

**Note:** disabling implicit sending of token can have weird side effects. For example,
if you want to list all models on the Hub, your private models will not be listed. You
would need to explicitly pass `token=True` argument in your script.

### HF_HUB_DISABLE_PROGRESS_BARS

For time-consuming tasks, `huggingface_hub` displays a progress bar by default (using tqdm).
You can disable all the progress bars at once by setting `HF_HUB_DISABLE_PROGRESS_BARS=1`.

### HF_HUB_DISABLE_SYMLINKS

If set, `huggingface_hub` will never create symlinks in the cache. Instead, files will be duplicated or moved directly into snapshot directories. This is a power-user feature making the cache directory run in a degraded mode where huge files ends-up duplicated on your hard-drive.

An example use case is when a shared network drive (e.g. NAS) is used as `HF_HUB_CACHE` across machines running different operating
systems. Symlinks created on Linux are not always traversable on Windows, leading to errors. Setting `HF_HUB_DISABLE_SYMLINKS=1` avoids this problem at the cost of disk-space deduplication.

### HF_HUB_DISABLE_SYMLINKS_WARNING

If you are on a Windows machine, it is recommended to enable the developer mode or to run
`huggingface_hub` in admin mode. If not, `huggingface_hub` will not be able to create
symlinks in your cache system. You will be able to execute any script but your user experience
will be degraded as some huge files might end-up duplicated on your hard-drive. A warning
message is triggered to warn you about this behavior. Set `HF_HUB_DISABLE_SYMLINKS_WARNING=1`,
to disable this warning.

For more details, see [cache limitations](../guides/manage-cache#limitations).

### HF_HUB_DISABLE_EXPERIMENTAL_WARNING

Some features of `huggingface_hub` are experimental. This means you can use them but we do not guarantee they will be
maintained in the future. In particular, we might update the API or behavior of such features without any deprecation
cycle. A warning message is triggered when using an experimental feature to warn you about it. If you're comfortable debugging any potential issues using an experimental feature, you can set `HF_HUB_DISABLE_EXPERIMENTAL_WARNING=1` to disable the warning.

If you are using an experimental feature, please let us know! Your feedback can help us design and improve it.

### HF_HUB_DISABLE_TELEMETRY

By default, some data is collected by HF libraries (`transformers`, `datasets`, `gradio`,..) to monitor usage, debug issues and help prioritize features.
Each library defines its own policy (i.e. which usage to monitor) but the core implementation happens in `huggingface_hub` (see [`send_telemetry`]).

You can set `HF_HUB_DISABLE_TELEMETRY=1` as environment variable to globally disable telemetry.

### HF_HUB_DISABLE_UPDATE_CHECK

By default, the `hf` CLI checks PyPI for a newer release at startup (at most once every 24 hours) and prints a one-line yellow warning to stderr when one is available, suggesting `hf update`. The check is already a no-op on dev and pre-release versions.

Set `HF_HUB_DISABLE_UPDATE_CHECK=1` to skip the PyPI request and silence the warning entirely. Useful in offline CI environments or when you prefer a quieter shell output.

### HF_HUB_DISABLE_XET

Set to disable using `hf-xet`, even if it is available in your Python environment. This is since `hf-xet` will be used automatically if it is found, this allows explicitly disabling its usage. If you are disabling Xet, please consider [filing an issue and including the diagnostics](https://github.com/huggingface/xet-core?tab=readme-ov-file#issues-diagnostics--debugging) information to help us understand why Xet is not working for you.

### HF_HUB_ENABLE_HF_TRANSFER

> [!WARNING]
> This is a deprecated environment variable.
> Now that the Hugging Face Hub is fully powered by the Xet storage backend, all file transfers go through the `hf-xet` binary package. It provides efficient transfers using a chunk-based deduplication strategy and integrates seamlessly with `huggingface_hub`.
> This means `hf_transfer` can't be used anymore. If you are interested in higher performance, check out the [`HF_XET_HIGH_PERFORMANCE` section](#hf_xet_high_performance)

### HF_XET_HIGH_PERFORMANCE

Set `hf-xet` to operate with increased settings to maximize network and disk resources on the machine. Enabling high performance mode will try to saturate the network bandwidth of this machine and utilize all CPU cores for parallel upload/download activity.

Consider this analogous to the legacy `HF_HUB_ENABLE_HF_TRANSFER=1` environment variable but applied to `hf-xet`.

To learn more about the benefits of Xet storage and `hf_xet`, refer to this [section](https://huggingface.co/docs/hub/xet/index).

### HF_XET_RECONSTRUCT_WRITE_SEQUENTIALLY

To have `hf-xet` write sequentially to local disk, instead of in parallel. `hf-xet` is designed for SSD/NVMe disks (using parallel writes with direct addressing). If you are using an HDD (spinning hard disk), setting this will change disk writes to be sequential instead of parallel. For slower hard disks, this can improve overall write performance, as the disk is not spinning to seek for parallel writes.

## Deprecated environment variables

In order to standardize all environment variables within the Hugging Face ecosystem, some variables have been marked as deprecated. Although they remain functional, they no longer take precedence over their replacements. The following table outlines the deprecated variables and their corresponding alternatives:


| Deprecated Variable         | Replacement        |
| --------------------------- | ------------------ |
| `HUGGINGFACE_HUB_CACHE`     | `HF_HUB_CACHE`     |
| `HUGGINGFACE_ASSETS_CACHE`  | `HF_ASSETS_CACHE`  |
| `HUGGING_FACE_HUB_TOKEN`    | `HF_TOKEN`         |

## From external tools

Some environment variables are not specific to `huggingface_hub` but are still taken into account when they are set.

### DO_NOT_TRACK

Boolean value. Equivalent to `HF_HUB_DISABLE_TELEMETRY`. When set to true, telemetry is globally disabled in the Hugging Face Python ecosystem (`transformers`, `diffusers`, `gradio`, etc.). See https://donottrack.sh/ for more details.

### NO_COLOR

Boolean value. When set, `hf` CLI will not print any ANSI color.
See [no-color.org](https://no-color.org/).

### XDG_CACHE_HOME

Used only when `HF_HOME` is not set!

This is the default way to configure where [user-specific non-essential (cached) data should be written](https://wiki.archlinux.org/title/XDG_Base_Directory)
on linux machines.

If `HF_HOME` is not set, the default home will be `"$XDG_CACHE_HOME/huggingface"` instead
of `"~/.cache/huggingface"`.
