Silocat is end-to-end encrypted file sharing and storage. Files are encrypted in your browser before a single byte moves, so the server stores ciphertext it cannot open. Drop a file, share a link, and nobody in between can read it.

Live at silo.cat. Run it yourself with the compose file below, or read the code and decide for yourself whether to believe us.

• Encrypted before it leaves. XChaCha20-Poly1305 per chunk, with a key Argon2id derives from your password on your device. Lose the password and the file is gone. No recovery, no backdoor, no exceptions.
• No account needed. Drop up to 20 GB anonymously and share the link. A key in your browser lets you manage those uploads later. Anonymous drops expire after seven days.
• Fast. Files are chunked and transferred directly against object storage, and the share link works before the upload finishes.
• Whole folders. Drop a directory and the structure survives the trip.
• Share links you control. Public, one-time, or off, with optional link passwords and expiry.
• Every feature on every tier. Paid plans buy space, not features. The free tier gets the same encryption and the same share controls.

Zero-knowledge is not zero-metadata. We can see that a 4 GB file was uploaded on a Tuesday. We cannot see what is in it. If your threat model includes the former, Silocat does not solve it.

Everything you need is here, including a bundled Postgres and MinIO, so a laptop or a single VPS is enough.

git clone https://github.com/clickswave/silocat
cd silocat
cp env.selfhost.example .env          # set the passwords and secrets
docker compose -f orchestration/docker-compose.selfhost.yml --env-file .env up -d

The app comes up at http://localhost:12001.

Optional integrations (SMTP, Google OAuth, Turnstile, Razorpay billing, GeoIP) switch on when their variables are filled in and stay off otherwise. See env.selfhost.example for the full reference.

A few things worth knowing:

• Storage defaults to the bundled MinIO. Point the CF_R2_* variables at Cloudflare R2, Backblaze B2 or any S3-compatible store for production.
• GeoLite2 lookups need MaxMind's free database, which their licence does not let us redistribute. Download it and set GEOLITE2_DB_PATH, or leave it blank to disable GeoIP.
• Retention is configurable: WATCHCAT_SHADOW_TTL_DAYS (anonymous drops, default 7), WATCHCAT_TRASH_TTL_DAYS (trash, default 30) and WATCHCAT_ORDER_TTL_DAYS (abandoned checkouts, default 7). If you change them, change the copy that promises them.
• Web deployment: the hosted silo.cat serves the frontend from Cloudflare Pages. The self-host compose runs the dev server for simplicity; for a hardened deployment put it behind a reverse proxy or switch to @sveltejs/adapter-node.

Two services and a scheduler.

web_server is the SvelteKit frontend and the only tier that talks to the API. It holds the infra secret, does the client-side crypto, uploads through presigned URLs, and serves the public share pages.

api_switch is a Rust/Axum backend on 0.0.0.0:31337. It owns all data and storage logic and runs its own migrations on startup. Every route requires a shared secret in a header (WEB_SERVER_COMMUNICATION_SECRET), so only our own backends can reach it. The /admin tree sits behind a second, independent secret and is served on its own hostname; the public zone returns 404 for it. Both gates fail closed, so an unset secret means reachable by nobody.

WatchCat is the same api_switch binary run with WATCHCAT_MODE=1. It enforces the retention the UI promises: expiring anonymous drops, emptying trash after its window, and reclaiming abandoned uploads.

Storage is any S3-compatible object store, addressed as three buckets: shadow for anonymous uploads, sanctum for account storage, dp for display pictures. Clients transfer chunks directly against storage, so ciphertext is all the store ever sees.

Every account gets an API key, visible and rotatable under Settings → API. Send it as X-Api-Key.

Because encryption happens client-side, the HTTP API takes ciphertext rather than files. The official client does that part for you:

npm install @clickswave/silocat-client

import { Silocat } from '@clickswave/silocat-client';

const silo = new Silocat({ apiKey: process.env.SILOCAT_API_KEY });

const file = await silo.upload(bytes, {
  name: 'contract.pdf',
  password: 'correct-horse-battery-staple'
});

const { url } = await silo.share(file.id, { type: 'public' });

Full reference at silo.cat/api, library source in packages/client. The raw endpoints are documented too, but using them means implementing Argon2id, chunking and XChaCha20-Poly1305 exactly as the app does. Get a parameter wrong and the upload succeeds while the file becomes permanently undecryptable, which is why the client exists.

The dev compose expects the monorepo layout used by the hosted deployment (external clickswave_network, shared Postgres). For hacking on Silocat alone, use the self-host compose above: it is fully self-contained.

# frontend
cd services/web_server && npm install && npm run dev

# backend
cd services/api_switch && cargo run

api_switch compiles against a checked-in query cache, so it builds without a database. If you change SQL, regenerate it with cargo sqlx prepare or CI will fail.

Found something? SECURITY.md has the reporting address, our response times, and an explicit scope. Please do not open a public issue for anything security-relevant.

The short version of what we guarantee: we hold ciphertext, and we do not hold your decryption passwords or anything that can recover them.

AGPL-3.0. If you run a modified Silocat as a network service, you have to offer your users the modified source. That is deliberate: the trust story of a zero-knowledge product depends on the code staying inspectable, wherever it runs.

Built by Clickswave Labs.