> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hypastack.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Introduction

> What Hypastack is and how the docs are organized.

## What is Hypastack

Hypastack is a file sharing and CDN hosting platform built in Europe. It's free to use, source-available, and run by a solo developer, not a company with a data-collection business model.

There are three separate pipelines behind it, and they don't all work the same way:

<CardGroup cols={3}>
  <Card title="Secure File Sharing" icon="lock" href="/secure-file-sharing">
    Zero-knowledge. Your browser encrypts the file before it leaves your device. Hypastack never sees the plaintext.
  </Card>

  <Card title="Permanent CDN Hosting" icon="globe" href="/cdn-hosting">
    Public, permanent asset hosting. Not encrypted, because a browser has to be able to render the file.
  </Card>

  <Card title="Developer API" icon="code" href="/api-reference/overview">
    Plain REST and JSON over both pipelines, for building your own tools on top of Hypastack.
  </Card>
</CardGroup>

## The zero-knowledge guarantee, precisely

The zero-knowledge property applies to **one pipeline only**: files uploaded through the Secure File Sharing flow on hypastack.com. Your browser encrypts the file client-side with AES-GCM (256-bit) before a single byte leaves your device. The decryption key lives in the URL fragment (the part after `#`), which browsers never send to a server. Hypastack's infrastructure is architecturally incapable of reading these files.

That guarantee does **not** extend to the other two pipelines:

* **CDN assets** are public by design, since they need to be rendered directly in a browser (e.g. `<img src>`). They're stored unencrypted. Hypastack strips EXIF, GPS, and camera metadata on upload, but the file content itself is readable by Hypastack and by anyone with the link.
* **Developer API uploads** are stored as received and are readable by Hypastack. There's no browser in the loop to hold an encryption key.

Read more in [How Encryption Works](/how-encryption-works).

## Account model

There's no email address or password. An account is a randomly generated account ID plus a passkey (a long random secret, not a chosen password), which Hypastack stores only as a one-way hash. See [Account & Passkeys](/account-and-api-keys).

## Where to go next

<CardGroup cols={2}>
  <Card title="Quickstart" icon="rocket" href="/quickstart">
    Create an account and share your first file in a few minutes.
  </Card>

  <Card title="Developer API" icon="terminal" href="/api-reference/overview">
    Upload, list, and delete files and CDN assets from your own code.
  </Card>
</CardGroup>