Introduction

We've received a lot of great technical questions from our community about how Plum Box actually works under the hood. In this post, we'll break down the architecture — how remote access is established, what happens to your data if Plum disappears, and exactly how your files are stored on the SSD.

1. Remote Access Architecture

Plum Box connects to your local network and provides access to your files from anywhere in the world. Here's how the connection is established:

Connection Flow

When you open the Plum app outside your home network, the connection happens in three phases, matching the diagram below:

Phase 1: Signaling (Arrow ①)

• Client initiates connection request via Signal Server

• Peers discover each other and exchange connection metadata

  
  

Phase 2: Discovery (Arrow ②)

• ICE determines the optimal connection path

• STUN server discovers public IPs and NAT types for both devices

  
  

Phase 3: Connection (Arrow ③)

• Direct P2P connection attempts via UDP hole punching

• Success: WireGuard tunnel is established (Green Line) for encrypted data transfer

• Fallback: If P2P fails, the connection routes through the TURN Relay automatically

Default Mode: Plum Relay

For most users, Plum Relay handles connectivity automatically with zero configuration.

How it works

Key points

• P2P First: The system always attempts a direct peer-to-peer connection. Relay is only used as fallback.

• End-to-End Encryption: All traffic is encrypted via WireGuard tunnel. Even when relayed, Plum servers cannot decrypt your data.

• No Port Forwarding Required: Works behind any NAT or firewall.

Protocol Stack

Advanced Mode: Port Forwarding + DDNS

For users who want complete independence from Plum's infrastructure:

Requirements

• Static IP or Dynamic DNS (DDNS) service

• Router with port forwarding capability

• Plum Box local IP address

Configuration

Router Port Forwarding

• External Port: 443 (or custom)

• Internal IP: [Plum Box Local IP]

• Internal Port: 443

• Protocol: TCP/UDP

Advantages

• Zero dependency on Plum servers

• Direct connection with lowest latency

• Full operational independence

A detailed port forwarding setup tutorial will be published before shipping starts in 2026.

2. What Happens If Plum Shuts Down?

This is one of the most common concerns we hear. Here's the technical breakdown:

Architecture: Local-First Design

Plum Box is architected with local-first principles. Your data never leaves your device unless you explicitly access it remotely.

Failure Scenarios

Key takeaway: Your data exists only on your SSD. Plum servers handle connection routing, not data storage.

Plum Server Dependencies

3. SSD Data Storage

File System: exFAT

Plum Box formats your SSD with exFAT for maximum cross-platform compatibility.

Why exFAT:

• Native read/write on Windows, macOS, and Linux without additional drivers

• No file size limitations for large video files

• If you remove the SSD, you can access files on any computer immediately

Directory Structure

When you connect your SSD to any computer, you'll see:

Structure details:

The directory structure in the Plum app mirrors exactly what's on the SSD. What you see in the app is what you get on disk.

Encryption (Optional)

Plum Box offers optional full-disk encryption for users who require additional security.

When encryption is enabled:

Plum Decryption Tool:

• Standalone application (Windows, macOS, Linux)

• Works independently of Plum Box or Plum servers

• Will be available for download and archived permanently

4. Storage Expansion

Single-Bay Architecture

Plum Box features one M.2 NVMe SSD slot (M-key). This design prioritizes:

• Compact form factor

• Lower cost

• Simplicity

Supported SSDs:

• Interface: M.2 NVMe (M-key)

• Form factors: 2280, 2260, 2242

• Capacity: Up to 8TB (tested)

When Storage Fills Up

Option A: Swap SSD in Plum Box

Option B: Access via External Enclosure

Accessing Old SSDs

Note: If encryption is enabled, you'll need the Plum Decryption Tool regardless of access method.

Summary

Design Philosophy

Plum Box is built on three principles:

• Your data stays yours — 100% local storage, no cloud dependency

• No lock-in — Standard file system, removable SSD, open protocols

• Graceful degradation — If Plum disappears, your data and access remain