Crux is becoming XTDB!

You can read the rename announcement, or head to this page on the new XTDB site (where you'll be taken in 10 seconds).


Crux S3

You can use AWS’s Simple Storage Service (S3) as Crux’s 'document store'.

Project Dependency

In order to use S3 within Crux, you must first add S3 as a project dependency:

  • deps.edn

  • pom.xml

juxt/crux-s3 {:mvn/version "21.04-1.16.0-beta"}

Using S3

Replace the implementation of the document store with crux.s3/->document-store

  • JSON

  • Clojure

  • EDN

  "crux/document-store": {
    "crux/module": "crux.s3/->document-store",
    "bucket": "your-bucket",
{:crux.document-store {:crux/module 'crux.s3/->document-store
                       :bucket "your-bucket"
{:crux.document-store {:crux/module crux.s3/->document-store
                       :bucket "your-bucket"


  • configurator (S3Configurator)

  • bucket (string, required)

  • prefix (string): S3 key prefix

  • doc-cache-size (int): size of in-memory document cache

Checkpoint store

S3 can be used as a query index checkpoint store.

Checkpoints aren’t GC’d by Crux - we recommend you set a lifecycle policy on your bucket to remove older checkpoints.

;; under :crux/index-store -> :kv-store -> :checkpointer
;; see the Checkpointing guide for other parameters
{:checkpointer {...
                :store {:crux/module 'crux.s3.checkpoint-store/->checkpoint-store
                        :configurator ...
                        :bucket "..."
                        :prefix "..."}}


  • configurator (S3Configurator)

  • bucket (string, required)

  • prefix (string): S3 key prefix

Configuring S3 requests

This is unfortunately currently only accessible from Clojure - we plan to expose it outside of Clojure soon.

While the above is sufficient to get crux-s3 working out of the box, there are a plethora of configuration options in S3 - how to get credentials, object properties, serialisation of the documents, etc. We expose these via the crux.s3.S3Configurator interface - you can supply an instance using the following in your node configuration.

Through this interface, you can supply an S3AsyncClient for crux-s3 to use, adapt the PutObjectRequest/GetObjectRequest as required, and choose the serialisation format. By default, we get credentials through the usual AWS credentials provider, and store documents using Nippy.

  • Clojure

{:crux.document-store {:crux/module 'crux.s3/->document-store
                       :configurator (fn [_]
                                       (reify S3Configurator