Nimbus

Every bucket, browsed like a folder.

A desktop browser for Amazon S3 and anything that speaks its API — Cloudflare R2, Backblaze B2, MinIO, your own endpoint. Open a bucket the way you open a drive: folders, thumbnails, a save panel. No web console, no command line, no account.

Download for MacApple SiliconWindows
Intel Mac? Download here
The Nimbus file list browsing a Cloudflare R2 bucket: an assets folder with thumbnails, sizes, dates and kinds, and the folder tree in the sidebar
The file list, browsing a Cloudflare R2 bucket. Captured from the app, not drawn.

S3 has no folders. Nimbus reads the slashes.

A bucket is one long, flat list of keys. Nimbus splits each key at its slashes, draws the prefixes as folders, and fetches each level only when you open it — the tree you expected, from storage that never had one.

Pick a key from an example bucket

The key photos/2026/kaikoura/whale-tail.jpg in bucket media-archive, split at its slashes:

Genusbucket
media-archive
Speciesfolder
photos
Varietyfolder
2026
Varietyfolder
kaikoura
Specimenfile
whale-tail.jpg

In the bucket this is one flat string. Nimbus asks for one level at a time, split on "/", and draws what comes back as folders.

As Nimbus shows it

  • media-archive
    • backups
    • exports
    • photos
      • 2025
      • 2026
        • kaikoura
          • coastline.jpg
          • whale-tail.jpg(selected)
    • readme.md

Everything a file browser does, pointed at a bucket.

Nimbus grid view showing a folder of image thumbnails

See it before you download it

Grid view draws images from short-lived presigned links, so you can tell what is in a folder without saving a single file.

The Nimbus sidebar folder tree expanded three levels deep with matching breadcrumbs

The whole tree, one level at a time

The sidebar opens as deep as the prefixes go and lists each level on first open. Every path is a URL, so a reload lands where you were.

Three files selected in Nimbus with download and delete actions in the toolbar

Gather several, act once

⌘-click or Ctrl-click to collect files, then save them through the native save panel or delete the lot in one go.

The Nimbus sort menu open over a file listing, showing eight sort orders

Sorted the way you think

Name, size, date or kind, either direction, as a list or a grid — and the choice survives a reload.

All your buckets, wherever they live.

Save a connection for every bucket you use and switch between them from the sidebar. Leave the endpoint empty for AWS; anything else is used as given, always path-style, so self-hosted gateways without wildcard DNS work too.

Example: four saved connections, one sidebar
ConnectionBucketRegionEndpoint
ProductionCloudflare R2Bucket: prod-assetsRegion: autoEndpoint: https://<account>.r2.cloudflarestorage.com
Media archiveAmazon S3Bucket: media-archiveRegion: ap-southeast-2Endpoint: — (AWS picks its own)
Offsite backupsBackblaze B2Bucket: offsite-backupsRegion: us-west-002Endpoint: https://s3.us-west-002.backblazeb2.com
Local MinIOMinIOBucket: release-buildsRegion: us-east-1Endpoint: http://localhost:9000

Paste a .env. Get a connection.

Drop your environment file into the form and Nimbus fills in all five fields, then checks the keys against the bucket before it saves anything.

  1. S3_BUCKET=offsite-backupsfills Bucket
  2. S3_REGION=us-west-002fills Region
  3. S3_ENDPOINT=https://s3.us-west-002.backblazeb2.comfills Endpoint
  4. S3_ACCESS_KEY_ID=••••••••••••fills Access key
  5. S3_SECRET_ACCESS_KEY=••••••••••••••••••••fills Secret key

Keys go to the keychain. Nowhere else.

Access keys are stored in macOS Keychain or Windows Credential Manager, never in Nimbus's settings file, and never handed back to the interface once saved. Requests are signed in the app's native core and go straight to your endpoint — there is no Nimbus account and no Nimbus server in between.

credentials.json
{
  "activeCredentialId": "c4f1…",
  "credentials": [{
    "id": "c4f1…",
    "label": "Offsite backups",
    "bucket": "offsite-backups",
    "endpoint": "https://s3.us-west-002…",
    "region": "us-west-002"
  }]
}
OS keychain
service
nz.co.delacour.nimbus
account
c4f1…
secret
stored, never shown