About
A thread you can follow.
Filum is 25 PDF tools that run entirely in your browser, built one at a time and verified on real documents before they appear. No account, no upload, no claims that haven't been measured.
The name is the principle
Filum is Latin for thread. For centuries, important documents were bound and sealed with thread — “red tape” is literally named for it. The thread was a promise: this document is intact, and nobody has touched it. That is the standard every tool is held to: the output is exactly what you chose, and nothing else is altered.
Your file never leaves your device
Every live tool runs entirely in your browser. There is no upload, no server-side copy, no “we delete it later” promise to take on faith — the file simply never leaves. Each tool ships with an automated browser test that captures network traffic during a real conversion and fails if a single request carries file data.
One verified tool at a time
A tool is listed only after it passes verification against real documents — real PDFs in a real browser, output bytes inspected, every failure path tested. There is no “basic support” and no hedged claim. If a tool can't meet that bar in full, it isn't listed.