Storage providers

MinIO

MinIO is the best solution we know of to self-host an S3-compatible object storage. It supports Windows and MacOS (and more), but we will only cover instructions for Linux here for brevity, although most of the information still applies to other platforms anyway.
First of all follow the official installation instructions and start up the server.

Create a bucket

Go to the Buckets or Object Browser tab and click on Create a Bucket. Give it a relevant name and leave all the features turned off.
Create a new bucket

You can now upload data into the bucket, either through the UI or with minio's command line tool.

Generate credentials

In the Access Keys tab, create a key pair. An access key and a private key will be generated for you.
By default, these have quite broad permissions. We recommend restricting the keys to a single bucket by specifying a custom JSON policy.
Create a new key pair

This policy is for granting bucket-level read/write permissions. Do not forget to edit the bucket name!

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "s3:GetObject",
        "s3:ListBucket",
        "s3:PutObject",
        "s3:DeleteObject"
      ],
      "Resource": [
        "arn:aws:s3:::<BUCKET NAME>",
        "arn:aws:s3:::<BUCKET NAME>/*"
      ]
    }
  ]
}

Remember to save your keys somehwere safe.
To make your bucket available over the internet, you need to create a tunnel using tools like Cloudflare Tunnel or ngrok, and remember the endpoint URL.