> For the complete documentation index, see [llms.txt](https://docs.couchdrop.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.couchdrop.io/how-couchdrop-works.md).

# How Couchdrop works

Couchdrop works differently from legacy SFTP and MFT infrastructure. There are a few key concepts that explain how the platform works and why it is different.

## Overview

Couchdrop works differently from a traditional file server. Understanding its virtual filesystem, connected storage, and managed transfer layer will make the rest of the platform easier to understand.

## Virtual filesystem

Couchdrop presents connected storage and systems through a virtual filesystem.

When you connect a platform such as SharePoint, Amazon S3, Google Drive, or an external SFTP server, it appears as a folder in Couchdrop.

That folder is a Couchdrop path to the connected system. The files themselves remain in the underlying storage platform.

For example:

**Couchdrop folder** → **SharePoint document library**

When you browse that folder in Couchdrop, you are viewing the files stored in SharePoint rather than copies stored separately in Couchdrop.

This lets you work with different storage platforms through a consistent filesystem while keeping your existing storage architecture.

{% hint style="info" %}
A folder in Couchdrop does not necessarily mean the files are stored by Couchdrop. It can represent a location in another connected platform.
{% endhint %}

<figure><img src="https://391958821-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FpokYqd27yrOUxIBhyvbF%2Fuploads%2FsIFWbfo7TMpAG6PdAFd7%2FOverview%20-%20File%20Browser.jpg?alt=media&amp;token=35a6ddde-3f56-4419-9eef-b19857681a25" alt=""><figcaption></figcaption></figure>

### Your data stays in your storage

When you use your own connected storage, Couchdrop transfers files directly to or from that storage rather than becoming another permanent place where those files are kept.

Couchdrop refers to this as **zero-custody transfer**.

Conceptually:

**Source → Couchdrop → Your storage**

rather than:

**Source → Couchdrop storage → Your storage**

For example, an SFTP user can upload a file to a Couchdrop folder that represents a SharePoint location. Couchdrop transfers the file into SharePoint, and SharePoint remains the system storing the file.

This allows you to retain control over where your business data is stored, including the storage platform's own residency, retention, and access policies.

{% hint style="info" %}
Zero-custody transfers apply when you use your own connected storage. Couchdrop-hosted storage is also available where required.
{% endhint %}

Couchdrop still retains the account information and metadata required to operate the service. Audit records may also contain information such as file and folder names.

### Access is separate from storage

Couchdrop separates **how files are transferred** from **where files are stored**.

A user or external system can access a Couchdrop folder without needing direct access to the storage platform behind it.

```mermaid
flowchart LR
    A["Partner<br/>connects over SFTP"]

    subgraph CD["Couchdrop"]
        B["Virtual folder"]
    end

    C["Your SharePoint storage"]

    A --> B
    B --> C
```

In the example above, the partner only needs the SFTP access you provide through Couchdrop. They do not need a SharePoint account or direct SharePoint permissions. They won't even know that you use SharePoint, they only see SFTP.

The same principle allows Couchdrop transfer methods and workflows to work with storage hosted elsewhere.

This separation means you can choose the transfer method required by a partner or system while retaining control of the underlying storage.

## Cloud-native SaaS

Couchdrop provides secure file transfer as a **managed SaaS platform**.

You configure the users, connections, virtual folders, and workflows that define how files move between your systems. Couchdrop operates the transfer infrastructure underneath them.

That means you do not need to deploy, patch, or maintain an SFTP server, virtual machine, local file transfer software, supporting scripts, or the infrastructure required to scale them.

Your storage and business systems remain where they are. Couchdrop provides the **secure transfer layer** that connects them to your other systems and external partners.

Platform updates, security maintenance, availability, and infrastructure scaling are managed as part of the Couchdrop service.

You manage how files should move. Couchdrop manages the infrastructure required to move them.

## API-first

Couchdrop provides an API for integrating platform administration and configuration into your own systems and processes.

This allows organizations to automate Couchdrop management rather than relying entirely on manual configuration through the web interface.

For API documentation, see the [Couchdrop Management API](https://developers.couchdrop.io/).