S3 Manager — A Self-Hosted Web UI for Managing S3-Compatible Storage Buckets

The Problem

My team and I rely heavily on S3-compatible object storage — Dell ECS, AWS S3, and a few other providers — for storing and retrieving data programmatically across multiple projects. The services themselves work great. What has always been a pain point, though, is browsing and managing those buckets through a decent UI.

For a long time, S3 Browser was our go-to desktop client. It gets the job done, but the free version limits you to a handful of bucket connections. Once you start working with multiple environments and multiple storage instances, you hit that wall pretty fast. Paying per seat for every team member just to browse a few files felt overkill.

Our next attempt was connecting IntelliJ IDEA to the S3 buckets using a plugin. That worked well — for the developers on the team. But here's the thing: not everyone on the team is a developer. QA engineers, Business Analysts, and other team members who needed occasional access to the buckets didn't have IntelliJ IDEA or any JetBrains IDE installed. Asking them to install a full-blown IDE just to browse some files was not a practical solution.

So we needed something that was:

• Web-based — accessible from a browser, no desktop app required
• Self-hosted — we control where it runs and who has access
• Simple — no complex setup, just point it at your S3 endpoint and go

Discovering cloudlena/s3manager

While searching for alternatives, I came across cloudlena/s3manager — an open-source web GUI written in Go for managing S3 buckets from any provider. I spun it up, pointed it at our S3 bucket instance, and it worked exactly as advertised. List buckets, upload files, download objects, create new buckets — all from the browser. Clean and functional.

But after using it for a bit, I had two concerns:

1. No Authentication

This was the big one. The application had zero authentication out of the box. Anyone who knew the URL could access the entire thing — browse every bucket, download any object, even delete files. In any real deployment scenario, this is a significant security risk.

Think about it: you're essentially exposing your entire object storage — potentially containing sensitive data, configuration files, backups, or customer data — to anyone on the network. Even in an internal network, that's a risk you don't want to take. A simple login page might not be enterprise-grade security, but it's a critical first line of defense that prevents casual unauthorized access and makes the tool viable for team use.

2. The UI Felt Dated

This is more of a personal preference, but the existing UI was built with Materialize CSS and felt a bit outdated. Since I was going to fork the project anyway, I figured I might as well give it a visual refresh too.

The Fork

So I created a fork at dimuthnc/s3manager and got to work — with a healthy dose of AI assistance, of course.

Here's what changed:

Authentication via Login Page

I added an opt-in authentication mechanism using two environment variables: USERNAME and PASSWORD. Both values are base64 encoded in the configuration to avoid storing plain-text credentials in Docker Compose files or environment configs.

When authentication is enabled:

• Any unauthenticated user trying to access any page (including deep links to specific buckets or objects) gets redirected to the login page
• After a successful login, the user is redirected back to the page they were originally trying to access — or to the main buckets page by default
• Sessions are managed via an HttpOnly, HMAC-signed cookie (s3manager_session)
• A random session secret is generated at each application startup, meaning all sessions are invalidated on restart — a simple but effective security measure
• A Logout button appears in the navbar when authentication is enabled
• Static assets are excluded from the authentication middleware so the login page renders correctly

If you don't set USERNAME and PASSWORD, the app runs exactly as before — no login, no changes to existing behavior. Fully backward-compatible.

Modern UI with shadcn/ui Design

I replaced the Materialize CSS with a custom stylesheet based on shadcn/ui design principles. The result is a cleaner, more modern interface with improved modals, toast notifications, tables, and empty states. I also swapped the Material Icons font dependency for inline SVG icons, keeping the build lightweight.

Screenshots

Login Page

Buckets Landing Page

File / Object View

How to Run It Yourself

Want to give it a try? Here's how to get it running.

Prerequisites

• Docker installed on your machine
• Docker Compose (comes bundled with Docker Desktop)

Option 1: Build from Source and Run with the Included Docker Compose

Step 1: Clone the repository

git clone https://github.com/dimuthnc/s3manager.git
cd s3manager

Step 2: Build the Docker image

docker compose build

Step 3: Start the stack

docker compose up

This spins up the S3 Manager along with two MinIO instances for testing. The included docker-compose.yml looks like this:

services:
  s3manager:
    container_name: s3manager
    build: .
    ports:
      - 8080:8080
    environment:
      # Authentication (base64 encoded: admin / password)
      - USERNAME=YWRtaW4=
      - PASSWORD=cGFzc3dvcmQ=
      # S3 Instance 1: my-first-instance
      - 1_NAME=my-first-instance
      - 1_ENDPOINT=s3:9000
      - 1_ACCESS_KEY_ID=s3manager
      - 1_SECRET_ACCESS_KEY=s3manager
      - 1_USE_SSL=false
      # S3 Instance 2: my-second-instance
      - 2_NAME=my-second-instance
      - 2_ENDPOINT=s3-2:9000
      - 2_ACCESS_KEY_ID=s3manager2
      - 2_SECRET_ACCESS_KEY=s3manager2
      - 2_USE_SSL=false
    depends_on:
      - s3
      - s3-2
  s3:
    container_name: s3
    image: docker.io/minio/minio
    command: server /data
    ports:
      - 9000:9000
      - 9001:9001
    environment:
      - MINIO_ACCESS_KEY=s3manager
      - MINIO_SECRET_KEY=s3manager
      - MINIO_ADDRESS=0.0.0.0:9000
      - MINIO_CONSOLE_ADDRESS=0.0.0.0:9001
  s3-2:
    container_name: s3-2
    image: docker.io/minio/minio
    command: server /data
    ports:
      - 9002:9000
      - 9003:9001
    environment:
      - MINIO_ACCESS_KEY=s3manager2
      - MINIO_SECRET_KEY=s3manager2
      - MINIO_ADDRESS=0.0.0.0:9000
      - MINIO_CONSOLE_ADDRESS=0.0.0.0:9001

Step 4: Open your browser and navigate to http://localhost:8080. Login with admin / password.

Option 2: Connect to Your Own S3-Compatible Storage

If you already have an S3-compatible storage (AWS S3, MinIO, DigitalOcean Spaces, Backblaze B2, etc.), you can use the pre-built Docker image directly. Create a docker-compose.yml like this:

services:
  s3manager:
    image: dimuthnc/s3manager:latest
    container_name: s3manager
    ports:
      - "8080:8080"
    environment:
      # Authentication (base64 encoded)
      # To generate: echo -n "yourusername" | base64
      - USERNAME=eW91cnVzZXJuYW1l
      # To generate: echo -n "yoursecurepassword" | base64
      - PASSWORD=eW91cnNlY3VyZXBhc3N3b3Jk

      # S3 Instance Configuration
      - 1_NAME=production-storage
      - 1_ENDPOINT=s3.amazonaws.com
      - 1_REGION=us-east-1
      - 1_ACCESS_KEY_ID=AKIAIOSFODNN7EXAMPLE
      - 1_SECRET_ACCESS_KEY=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
      - 1_USE_SSL=true

      # Optional: Add more instances
      # - 2_NAME=staging-minio
      # - 2_ENDPOINT=minio.internal.company.com:9000
      # - 2_ACCESS_KEY_ID=minioadmin
      # - 2_SECRET_ACCESS_KEY=minioadmin
      # - 2_USE_SSL=false
    restart: unless-stopped

Replace the placeholder values with your actual S3 credentials and endpoint. Then run:

docker compose up -d

Environment Variables Reference

Here's a quick reference of the key environment variables:

Variable	Description
USERNAME	Login username, base64 encoded. Auth is enabled only when both USERNAME and PASSWORD are set.
PASSWORD	Login password, base64 encoded.
N_NAME	Display name for S3 instance N (e.g., 1_NAME, 2_NAME)
N_ENDPOINT	S3 endpoint for instance N
N_ACCESS_KEY_ID	Access key for instance N
N_SECRET_ACCESS_KEY	Secret key for instance N
N_USE_SSL	Whether to use SSL for instance N (true/false)
N_REGION	AWS region for instance N (optional)
PORT	Port the app listens on (default: 8080)
ALLOW_DELETE	Enable delete buttons (default: true)

To generate base64-encoded values for your credentials:

echo -n "admin" | base64       # Output: YWRtaW4=
echo -n "mypassword" | base64  # Output: bXlwYXNzd29yZA==

Docker Hub

The image is published on Docker Hub as dimuthnc/s3manager:

docker pull dimuthnc/s3manager:latest

Tag	Description
latest	Latest stable build
v1.1.0	Authentication support (login page, logout)
v1.0.0	Initial release with shadcn/ui redesign

Wrapping Up

This is not a ground-up rewrite — it's a focused fork that adds the two things that were missing for our use case: a login page and a modern UI. The original cloudlena/s3manager project did the heavy lifting with a solid Go backend and S3 integration. I just built on top of it.

If you're looking for a lightweight, self-hosted web UI to manage your S3-compatible storage and want something that your entire team — developers and non-developers alike — can use from a browser, give dimuthnc/s3manager a try. Feel free to open issues or submit PRs if you have ideas for improvements.