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tagdrop

Decode data URIs in QR codes
TagDrop turns small files — text, HTML pages, images, audio, SVGs — into self-contained QR codes that work completely offline. Print one on a sticker or sheet of paper and leave it somewhere; anyone with the TagDrop app (or any QR scanner that follows tagdrop: links) can scan it and view the content immediately, with no internet connection, server, or account required.

Think of it as a digital geocache: instead of a logbook in a box, the "cache" is the QR code itself.

What you can do with it


  • Drop a single page — encode text, an HTML page, an SVG image, or JSON into one QR code, either in-app (Create Cache) or with the web generator.

  • Drop a whole "paper" — a printable sheet with a directory QR code (a paper manifest) plus one QR per file, built in-app (Create Paper) or with the web generator. Pages can link to each other with ordinary relative links, so a small static site survives being printed and scanned back in.

  • Spread large content across multiple codes — split a payload too big for one QR into a manifest plus chunk codes placed along a trail. The app collects chunks in any order and reassembles and verifies them.

  • Build trails and collections — link papers together with location hints, or tag a loose set of stickers with a shared collection so they group into one card on the home screen and map, even though each code is independently scannable.

  • Browse offline — scanned pages render in an in-app viewer. The Collections, History, and Map tabs let you revisit, locate, and manage everything you've found.



How it works

Every code carries a tagdrop: URI — a CBOR sequence (version, type, and payload map), Base45-encoded so it packs efficiently into a QR code's alphanumeric mode. Content can optionally be DEFLATE-compressed. IDs are content-addressed (SHA-256 based), so identical content always gets the same ID regardless of who created it.

Status

V2.0 — CBOR-sequence envelope encoding, paper manifests with multi-file directories and relative-link navigation, geographic trails via "related" hints, ad-hoc collections, an in-app scanner with a live scan board, and a Map tab for located finds.
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Versions

Although APK downloads are available below to give you the choice, you should be aware that by installing that way you will not receive update notifications and it's a less secure way to download. We recommend that you install the F-Droid client and use that.

Download F-Droid
  • Version 2.0.0 (5) suggested Added on Jun 21, 2026

    This version requires Android 5.0 or newer.

    It is built and signed by F-Droid, and guaranteed to correspond to this source tarball.

    Permissions
    • access approximate location only in the foreground
      This app can get your approximate location from location services while the app is in use. Location services for your device must be turned on for the app to get location.
    • access precise location only in the foreground
      This app can get your precise location from location services while the app is in use. Location services for your device must be turned on for the app to get location. This may increase battery usage.
    • take pictures and videos
      This app can take pictures and record videos using the camera while the app is in use.
    • have full network access
      Allows the app to create network sockets and use custom network protocols. The browser and other applications provide means to send data to the internet, so this permission is not required to send data to the internet.
    • com.github.mofosyne.tagdrop.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION

    Download APK 6.2 MiB PGP Signature | Build Log

  • Version 1.3 (4) - Added on Sep 01, 2015

    This version requires Android 4.0.3 or newer.

    It is built and signed by F-Droid, and guaranteed to correspond to this source tarball.

    Permissions
    • have full network access
      Allows the app to create network sockets and use custom network protocols. The browser and other applications provide means to send data to the internet, so this permission is not required to send data to the internet.

    Download APK 1 MiB PGP Signature | Build Log

  • Version 1.2 (3) - Added on Aug 31, 2015

    This version requires Android 4.0.3 or newer.

    It is built and signed by F-Droid, and guaranteed to correspond to this source tarball.

    Permissions
    • have full network access
      Allows the app to create network sockets and use custom network protocols. The browser and other applications provide means to send data to the internet, so this permission is not required to send data to the internet.

    Download APK 1 MiB PGP Signature | Build Log

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