bit Mule

What is it?

bitMule is an end-to-end encrypted file transfer tool. Send something directly, peer-to-peer, for free — or subscribe to hosted uploads and a hosted inbox so you can send and receive without either device staying online. Desktop, CLI, web and mobile all speak the same protocol, and the server is built to never see what's inside your files, encrypted or not.

Privacy and security

How it's protected

End-to-end encryption in two layers — files are compressed, padded and encrypted before they ever leave your device.
The server never sees your key. For direct shares, the decryption key lives in a piece of the link itself that's never sent anywhere.
Optional password protection layered on top of the link-based key, for an extra step when you want one.
Identifying metadata — EXIF and similar — is stripped automatically before encryption.

What we deliberately don't do

No server-side virus scanning.
No link previews or thumbnails.
No watermarking.
No content-based audit trails.
All of these would require seeing inside your files — and by design, we can't.

Supported platforms (and prices)

Desktop app	free	open source
CLI	free	open source, scriptable
Web app	free	no sign-up for direct (P2P) sharing
Android app	5€	one-time purchase
iOS app	10€	one-time purchase

Pro services (hosted uploads and hosted inbox) work identically across every platform above.

Free features

Direct sharing P2P

Share files and folders instantly via a link — the recipient's browser or app starts downloading automatically.
No account needed to send or receive.
Works across desktop, CLI and web today.

Desktop, CLI & web

Full-featured, no paywall — desktop and CLI are open source; the web app needs no install.
The web app doesn't do background sync or auto-upload — a browser limitation, not a pricing one.
Mobile apps add native convenience (share-sheet, background sync, camera roll, push) for a small one-time fee, but do nothing the web app can't already do.

Paid features

Hosted uploads

Upload once, get a persistent link that works any time — your device doesn't need to stay online.
Unique per-recipient links, individually revocable, or a shared link with a download cap.
Mix both on the same upload.
Default 7-day expiry, adjustable account-wide or per upload.
A single-use link is only spent once the download completes successfully.

Hosted inbox

Let anyone send you files without your device being online.
One-time upload links via app, CLI or REST API.
Standing upload access for regular contacts, with configurable storage and file-count limits.
Uploads encrypt directly to your identity; only your private key opens them.
Batch links and webhooks for events, classes, vendor lists, or your own automation.

Trust & contacts

Add a contact by public key or fingerprint, or import by username with a fingerprint confirmation step.
Optional multi-device key sync, or keep a key on one device for maximum control.
Key rotation is self-signed by the old key — contacts update automatically, in-flight links still resolve.

Pricing for paid features

Basic

100GB storage · 500GB bandwidth

4€_/mo

Extended

500GB storage · 2TB bandwidth

10€_/mo

Identity verification (payment + email, at minimum) is required for both tiers — abuse mitigation, not a trial gate.
Billed at Extended but usage stays within Basic's caps for a period → auto-downgraded to the Basic price for that period.
Under 20% of your billed tier's caps (peak storage and summed bandwidth) → cancel for a full refund on that period. Trial insurance, not a recurring rebate.

overage, flat & metered: storage 0.006€/GB·mo bandwidth 0.0025€/GB no packs to buy, nothing to roll over

Crypto details

for those who care — spec v1, reviewed 2026-09-03

AES-256-GCM bulk cipher / X25519 ephemeral exchange / forward secrecy by design / fails closed, never to plaintext

Key exchange

Fresh X25519 keypair per session; DH secret HKDF-split into independent wrap and meta keys.
Ephemeral privates are wiped right after use, so a leaked link later can't reconstruct a past session's key.

Bulk transfer

Bulk stream key B is fresh per file, chunk-indexed nonces, AEAD on every chunk.
Missing chunk at close-out → transfer rejected, not silently corrupted.

Failure mode

No plaintext fallback — a failed key exchange errors the transfer instead of downgrading.fail closed
Optional Ed25519 signature proves sender identity without breaking anonymous sends.