---
title: Cache storage backends
description: |
  Cache backends let you manage your build cache externally.
  External cache is useful to create a shared cache that can help
  speed up inner loop and CI builds.
keywords: build, buildx, cache, backend, gha, azblob, s3, registry, local
aliases:
  - /build/building/cache/backends/
---

To ensure fast builds, BuildKit automatically caches the build result in its own
internal cache. Additionally, BuildKit also supports exporting build cache to an
external location, making it possible to import in future builds.

An external cache becomes almost essential in CI/CD build environments. Such
environments usually have little-to-no persistence between runs, but it's still
important to keep the runtime of image builds as low as possible.

The default `docker` driver supports the `inline`, `local`, `registry`, and
`gha` cache backends, but only if you have enabled the [containerd image store](/manuals/desktop/features/containerd.md).
Other cache backends require you to select a different [driver](/manuals/build/builders/drivers/_index.md).

> [!WARNING]
>
> If you use secrets or credentials inside your build process, ensure you
> manipulate them using the dedicated
> [`--secret` option](/reference/cli/docker/buildx/build.md#secret).
> Manually managing secrets using `COPY` or `ARG` could result in leaked
> credentials.

## Backends

Buildx supports the following cache storage backends:

- `inline`: embeds the build cache into the image.

  The inline cache gets pushed to the same location as the main output result.
  This only works with the [`image` exporter](../../exporters/image-registry.md).

- `registry`: embeds the build cache into a separate image, and pushes to a
  dedicated location separate from the main output.

- `local`: writes the build cache to a local directory on the filesystem.

- `gha`: uploads the build cache to
  [GitHub Actions cache](https://docs.github.com/en/rest/actions/cache) (beta).

- `s3`: uploads the build cache to an
  [AWS S3 bucket](https://aws.amazon.com/s3/) (unreleased).

- `azblob`: uploads the build cache to
  [Azure Blob Storage](https://azure.microsoft.com/en-us/services/storage/blobs/)
  (unreleased).

## Command syntax

To use any of the cache backends, you first need to specify it on build with the
[`--cache-to` option](/reference/cli/docker/buildx/build.md#cache-to)
to export the cache to your storage backend of choice. Then, use the
[`--cache-from` option](/reference/cli/docker/buildx/build.md#cache-from)
to import the cache from the storage backend into the current build. Unlike the
local BuildKit cache (which is always enabled), all of the cache storage
backends must be explicitly exported to, and explicitly imported from.

Example `buildx` command using the `registry` backend, using import and export
cache:

```console
$ docker buildx build --push -t <registry>/<image> \
  --cache-to type=registry,ref=<registry>/<cache-image>[,parameters...] \
  --cache-from type=registry,ref=<registry>/<cache-image>[,parameters...] .
```

> [!WARNING]
>
> As a general rule, each cache writes to some location. No location can be
> written to twice, without overwriting the previously cached data. If you want
> to maintain multiple scoped caches (for example, a cache per Git branch), then
> ensure that you use different locations for exported cache.

## Multiple caches

BuildKit supports multiple cache exporters, allowing you to push cache to more 
than one destination. You can also import from as many remote caches as you'd 
like. For example, a common pattern is to use the cache of both the current 
branch and the main branch. The following example shows importing cache from 
multiple locations using the registry cache backend:

```console
$ docker buildx build --push -t <registry>/<image> \