Sharing books

Sharing books

Sharing turns one book into a web page at tsumihon.app/s/… that anyone holding the link can open. There are no accounts on that page and nothing to install to read it.

Tap Share on a book, then Share link. Tsumihon creates the page and hands the URL to your usual share sheet, so you can send it however you normally would.

The link is a public URL. Anyone who has it can open the page — there is no password and no sign-in. It is unguessable rather than protected: the address contains about 52 bits of randomness, so nobody finds it by trying. Treat it the way you would treat any link you send someone: whoever you give it to can pass it on.

What the page shows

A share is a snapshot, taken when you create the link. It carries only bibliographic information:

  • Titles, artist, circle, parody, characters, cosplayers
  • Tags, conventions, type, format, page count, release date
  • Publisher, magazine, series and volume, ISBN, description
  • The cover, and the source links stored on the book

It does not carry your price, notes, physical location or condition, shelf assignment, download status, ratings, categories, or anything that identifies your account. Those fields are excluded by an allowlist rather than by a filter, so a field added to Tsumihon in future is private unless it is deliberately added to a share.

Because it is a snapshot, editing the book afterwards does not change what the page shows, and deleting the book does not leave the page working — deleting a book cancels its link.

The cover is blurred

The page shows the cover blurred, and reveals it on a tap. Link previews — in chat apps, on lock screens — always use the blurred version, so nothing explicit appears in a group chat before anyone chooses to open the link.

The cover is served through Tsumihon rather than linked from its original source. That means the source site never sees who is reading the page, and its address does not appear on it.

Every link expires seven days after you create it. You do not have to do anything.

You can also cancel at any time. Settings → Privacy → Active share links lists everything you currently have shared, how many times each link has been opened, and how long each has left. Cancelling is immediate — the page starts saying the owner turned the link off, and the cover stops being served within the hour.

The “opened” count is there so cancelling early is an informed decision: if the person you sent it to has already opened it, you know it is safe to turn off.

Sharing the same book again reuses its existing link rather than creating a second one, so there is never more than one live link per book, and never any doubt about which one you are cancelling.

Limits

You can have 20 links live at once, and create 20 per hour. If you reach the ceiling, Tsumihon says so and offers the Active share links screen so you can cancel one — nothing is ever cancelled automatically, because a link you have already sent someone should not stop working without you deciding it should.

Creating and cancelling both need a connection. A link has to exist on the server before you send it to anybody, so it cannot be created offline. The Shared badge on a book works offline.

Following a share link opens the web page, not the app — on purpose, so the page is readable by people who do not use Tsumihon, and so you can check what a recipient will see.

If you do have Tsumihon, the page has an Open in Tsumihon button. That shows you exactly what will be added before anything enters your library, and warns you if it looks like a book you already own. If you are not signed in, Tsumihon remembers which share you were opening and picks it up again once you are.

Imported details are marked as coming from a share, so they are kept without overriding anything you entered yourself or anything a source provided.

Search engines

Share pages are excluded from search engines and are not listed anywhere. A link reaches whoever you send it to and nobody else.