Filen Review 2026: What "Open Source" Actually Covers

Filen is a German encrypted-storage provider with a strong privacy pitch and, unusually for this market, a real open-source presence. Its front page makes two claims that lean on each other:

"Filen was built around zero-knowledge end-to-end encryption. Neither we, as a service provider, nor any other service agency will ever have access to your files."

"Filen always tries to be as transparent as security can be. No secret financiers or large corporations in the background. All of our apps are open source."

Both sentences are accurate. The second one is also narrower than most readers take it to be, and the gap between "our apps are open source" and "we are open source" is the single most useful thing to understand before choosing Filen for privacy.

What is actually published?

Filen's own menu has an entry for its open-source code. It does not open a page on filen.io — it redirects straight to github.com/FilenCloudDienste, a verified organisation whose description reads "Zero knowledge end-to-end encrypted cloud storage, redefined."

That organisation holds 26 repositories, most of them under the GNU Affero General Public License v3.0. Checked in September 2026, they are:

• Apps you install — filen-desktop (Windows, macOS, Linux), filen-web (the web and desktop front end), filen-cli, filen-mobile (archived), filen-drive-legacy, plus the iOS file provider and Android documents provider.
• Developer kits — filen-sdk-ts, filen-sdk-go, filen-rs, filen-ts.
• Integrations you run — filen-rclone, filen-webdav, filen-s3, filen-network-drive, filen-sync, filen-relay.
• Documentation and third-party utilities — filen-docs, aws4-express, browser-image-compression, and several small React Native and filesystem helpers.

Every one of those runs on your computer, your phone, or infrastructure you rent yourself. Two of them have the word "server" in their descriptions — filen-webdav "starts a WebDAV server for a single or multiple Filen accounts" and filen-s3 "starts a S3 server for a Filen account" — and filen-relay is a Rust service whose README says it "provides a convenient way to serve your Filen Drive via HTTP/WebDAV/S3", installed by Docker on your own hardware. None of the three is Filen's storage backend.

The service that receives your uploads, stores the ciphertext, authenticates you and bills you is not in the list, and Filen does not claim it is. There is no page on filen.io stating the server is closed, and none claiming it is open.

Does that make the zero-knowledge claim false?

No — and this is the part worth being careful about.

In a genuinely end-to-end encrypted system, the encryption happens in the client before anything leaves your device. The client is exactly what Filen publishes. Anyone with the skills can read filen-desktop or filen-sdk-ts and confirm that files are encrypted locally with AES-256 and that the key never goes to the server. That is a real, checkable guarantee, and most storage providers offer nothing comparable.

What open clients cannot tell you is what the server does with what it receives: how accounts are recovered, what metadata is retained, how long deleted blocks persist, or whether the build you downloaded matches the source you read. For those you are trusting Filen's word and German data-protection law, not an audit of published code.

This is also the standard arrangement. Proton Drive publishes its clients and keeps its backend closed. So does Tresorit. So does almost everyone in this category. Filen is not an outlier and is not being deceptive — its sentence says "apps", and its apps are open source. The useful question to ask any provider is not are you open source but which part.

What does the free plan actually give you?

Filen's free tier is real, not a trial, and it does not ask for a card. On the pricing page it sits behind the Starter tab: "Starter free", 10 GiB, listed at "0€ lifetime". Client-side encryption and zero-knowledge technology are both included, which is more than most free tiers offer.

One line on that card matters more than the storage number:

"Filen-to-Filen sharing only (no public links)"

On the free plan you cannot create a public share link at all. You can share with another Filen account, and that is the limit — so you cannot send a file to a client, a colleague or a family member who does not sign up. Every paid card replaces that line with plain "File sharing". The free plan also carries "Limited notes" and "Limited chats" where paid plans say unlimited.

For comparison, pCloud and MEGA both let free users create public links and charge only to put a password on one. Filen's limit is harder: the link itself is the paid feature.

The free card also carries a caveat that privacy-minded readers should notice:

"Our free tier and free storage work best on standard residential internet connections. Registration via VPNs, Tor, proxies, relays, or hosting networks may be excluded from free storage."

What Filen costs

All prices are in euros, and Filen accepts major credit cards and PayPal.

The monthly figures are genuinely monthly — paying annually is cheaper per month, not a disguised annual-only price, which is a fairer pricing page than most of this market offers. Plans stack: Filen notes you can "Combine two Pro X plans for 20 TiB on one Filen account, with no upper limit."

Lifetime plans are gone. Filen's own pricing FAQ answers "Can I buy a lifetime plan?" with: "We have removed our lifetime plans from the lineup for an indefinite period." If you are reading an older roundup that lists a Filen lifetime deal, it is out of date.

Corrections to the previous version of this page

This article previously described Filen as "an open-source, end-to-end encrypted zero-knowledge cloud storage provider" without qualification, and said "the open-source nature allows community audits for transparency". As set out above, the published code covers the clients, not the service, so community audit reaches the client-side encryption and stops there.

It also stated that Filen skips "features like WebDAV support", which is incorrect — filen-webdav is one of the published repositories. And it quoted prices of "about $5/month for 100GB" and "Pro at $10/month for 2TB+". No such plans exist; Filen prices in euros and the figures are in the table above.