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

# Core Concepts: What Makes Zas Different

> Zas is built on three ideas: everything expires, files deduplicate globally, and privacy is blind by design. Learn how each one works.

Zas is not a storage service. It is a corridor for files, images, video, and short text. Three design choices make that corridor fast, private, and clean: expiry, global deduplication, and blind privacy.

## The three pillars

<CardGroup cols={3}>
  <Card title="Expiry" icon="clock" href="/en/concepts/expiry">
    Every item deletes itself after a fixed lifetime. Nothing accumulates, and nothing expires silently.
  </Card>

  <Card title="Global dedup" icon="zap" href="/en/concepts/dedup">
    Files are content-addressed. If a file already exists anywhere in Zas, it sends in about one second, no matter the size.
  </Card>

  <Card title="Privacy" icon="shield" href="/en/concepts/privacy">
    Encrypted at all times. Nobody reads what you send. No list exists of who has what.
  </Card>
</CardGroup>

## Why these matter together

Expiry keeps your channels clean. Global dedup makes large files move instantly. Privacy means the service cannot build a map of who holds what, even if it wanted to. Combined, they create a dispatcher that feels like a universal clipboard: paste on one device, grab on another, and trust that the corridor forgets.

## What to read next

* [How expiry works](/en/concepts/expiry)
* [How deduplication works](/en/concepts/dedup)
* [How privacy works](/en/concepts/privacy)