---
title: How quickS3 is built
description: "The Cloudflare services behind quickS3, where each kind of data lives, how organisations are kept apart, and what that means for your files."
section: Security
order: 40
audience: [owner, admin]
status: published
lastVerified: 2026-09-15
sources:
  - docs/ARCHITECTURE.md
  - src/objects/organisation.ts
  - src/objects/organisation-db.ts
  - wrangler.jsonc
---

quickS3 runs on Cloudflare's platform. This page is for people who want to know where things live before trusting it with their storage.

## One store per organisation

Each organisation has its own Cloudflare Durable Object: a small, isolated database with a unique, unguessable ID. It holds everything about that organisation:

- members and their roles,
- custom roles and rules,
- connections and their encrypted storage keys,
- AI client access,
- the audit log.

Every request for an organisation goes to that one store, which checks membership and roles itself. Because there's exactly one copy, changes are immediate: when you remove someone or change a role, their very next request sees it.

## Around it

| Service | Holds |
| --- | --- |
| Cloudflare Workers | The web app, the API, and the MCP server. |
| Cloudflare D1 | The list of user accounts and sign-in details, and which organisations each person belongs to. Not permissions. |
| Cloudflare KV | Short-lived sign-in data for AI clients while they're being approved. |
| Cloudflare Workflows | Multi-step jobs like sending invitations and removing members. |

The organisation switcher and a few lists read from D1, so right after a change they can take a moment to catch up. Access decisions never do.

## Trust boundaries

- Storage keys are encrypted at rest and only decrypted on quickS3's servers, to list files and sign links.
- File contents go directly between people and your storage provider, except when an Owner turns on the backend upload fallback. See [where your files travel](/docs/security/file-data/).

## What this page doesn't promise

It describes how quickS3 works today. It isn't a guarantee of data location, backup, or recovery. quickS3 doesn't back up your files, and the audit log is kept for 14 days. For what that means in practice, see [security model and limitations](/docs/security/model/).