Scrinium is an encrypted Markdown notes app: a private Markdown editor with a Typora-style writing experience, where the notes are encrypted on your device before they are stored or synced. The format is deliberately the most ordinary one available, and the encryption is deliberately the least ordinary.
Every proprietary notes format asks for the same thing: trust that the company outlives your notes. Markdown asks for nothing. It is plain text with a handful of conventions — # for a heading, ** for emphasis — and it will still be readable when the app, the vendor, and the standard all look different.
It also happens to be the format that technical people already keep their thinking in: README files, commit messages, documentation, research notes, and everything an LLM ever writes. Storing notes as Markdown means your notebook plugs into that world instead of sitting beside it.
Markdown solves portability and says nothing about privacy. A folder of .md files synced to a cloud drive is perfectly portable and perfectly readable by the drive. That is the default most people live with: their most personal text, in plain sight, on someone else’s computer.
Encryption is what makes the portability safe to use. If the notes are sealed on your device, the copy in the cloud is a pile of ciphertext, and the only thing that opens it is a key that never left your machine. Portability without exposure is the whole idea.
Pick a private notes app and you usually accept a plain editor. Pick a powerful Markdown editor and you usually accept that the service can read everything. The products that do encryption well tend to treat writing as a solved problem, and the products that write well treat encryption as a plugin.
Scrinium is the intersection, on purpose: inline Markdown WYSIWYG, a zero-knowledge key hierarchy, and sync that is free and unlimited rather than metered. See the comparisons for how that lands against each alternative.
Headings, lists, task lists, tables, blockquotes, and fenced code with syntax highlighting render in place while the Markdown stays the source of truth.
Full-text search runs locally over notes decrypted in memory. Your queries are not sent anywhere, so the search index cannot become a profile of what you think about.
Images and files are encrypted under their own keys and stored as separate blobs, so a note stays small and a leaked attachment tells an attacker nothing.
KaTeX for math, Mermaid for diagrams, and fenced code blocks with syntax highlighting — the writing a Markdown user actually does on a Tuesday.
The last 30 revisions of a note ride inside the encrypted note blob, so restore works without a server that keeps plaintext copies of your drafts.
Structure without a database: folders you can nest, quick capture, and a client-side graph built from [[wikilinks]] in your notes.
Export the whole vault as Markdown at any time, or as an encrypted archive if you want to move it while keeping it sealed. Import reads Markdown files, and an encrypted backup restores into another vault — all of it client-side, so the export path does not depend on the service staying honest.
A notebook you cannot leave is a notebook you are renting. This one you own, in a format that has outlived every app that has ever adopted it.
A Markdown editor that encrypts notes on your device before they are stored or synced, so the service holding them cannot read them. Scrinium renders Markdown inline as you type and keeps the Markdown itself as the stored format.
Because Markdown is a text format rather than an application format. It survives the app that made it, diffs sensibly in version control, opens in every editor written in the last thirty years, and can be read in a terminal if it comes to that.
Yes, locally. Scrinium decrypts notes in your browser’s memory and searches there, so you get instant full-text search without a server ever seeing a query or an index.
Yes — export the whole vault as Markdown, or as an encrypted archive if you would rather move it while keeping it sealed. Import accepts Markdown files, and encrypted backups restore into another vault.
Encryption happens when a note is saved or synced, not on every keystroke, and the editor works on decrypted content in memory. The cost is a fraction of a second on save, not a lag while typing.
Free and unlimited: notes, encrypted sync, and devices.