A paper is a long, figure-heavy PDF, and PDF is one of the four formats whose rendering has been verified on a clean device in FoldRender. This is the procedure for getting a paper onto an unfolded Fold and reading it properly — from a browser download, an email attachment or the repository the paper's code lives in — plus a straight account of what a reader-only app does not give you as a researcher.
FoldRender is on the Play Store as FoldRender: Git Repo Reader, package id dev.foldrender.app, free and distributed worldwide. Install it the ordinary way — no allow installs from this source prompt to approve, and updates arrive on their own. The app declares minSdk 30, so it needs Android 11 or newer; Play will tell you if a device is below that rather than letting you install a build that cannot run.
However the PDF arrives — saved from the browser, an email attachment, a file in Drive or Downloads — it lands in ordinary Android storage. Tap it in the Files app and choose Render in the “Open with” list: FoldRender registers for application/pdf by MIME type and for .pdf by extension, so it is offered even by providers that serve the file with a vague content type. From inside the app, the folder icon in the top bar — or Open a file on the empty screen — picks the same file through the system document picker.
If the paper has a public repository — reference implementations live on GitHub all over research — clone it: branch glyph in the top bar, paste the HTTPS URL into Clone an HTTPS repository URL, tap Clone. A public repository clones anonymously, with no account and no token. A PDF checked into that repository opens from the same tree as the source, which is the whole point: the figure on page 7 and the function that produced it, one screen apart.
In the Files tab every row carries a type badge, and PDFs are badged PDF in red — easy to spot in a repository of source files. Unfolded, the tree stays on the left and the paper renders on the right; folded, the paper takes the whole screen and the tree becomes a back step.
The header above the page strip reads N pages · page M, and M updates live as you scroll. A horizontal strip of page thumbnails sits alongside the document; tapping a thumbnail jumps the main list to that page — the working substitute for skimming back to figure 3, then forward again.
The text-size icon opens the Reading sheet: Theme (System / Light / Dark), a Text size slider from 80% to 160%, a Line width slider from 480 dp to 1200 dp, and a serif switch. Pages re-render at the new width rather than upscaling a stale bitmap — rotating or refolding does not blur the page. One-page-at-a-time rendering behind a mutex keeps memory flat even on a 200-page document.
A PDF opened from local storage needs no connection, and every renderer in the app works on the local file. A paper read on a plane behaves exactly like a paper read at a desk.
PDF goes through Android's own PdfRenderer — no native libraries added to the APK, and pages look the way the rest of the system renders them. Detection scores name, MIME type and magic bytes together, so a paper whose filename lost its extension still opens as a PDF if its first bytes are %PDF.
The same pane renders the Markdown README, the highlighted source, the notebooks and the PDF, from one tree. For a paper with a public implementation, that beats a standalone PDF viewer: the equation and the line of code that implements it are a thumbnail tap apart.
Reading a local PDF involves no network, and even inside a cloned repository the only operations that touch the remote are git ones — Pull, for when the authors push a revision.
The honest list — shipped-but-unverified behaviour included, so you can tell before installing whether this build does the thing you came for.
Four apps people actually reach for, and the one axis that separates them: whether the repository ends up on the phone, and whether anything renders it once it is there.
| Tool | Download price | Where you get it | Clones to the device | Renders PDF / notebook / Markdown | Editor or shell |
|---|---|---|---|---|---|
| FoldRender 0.8.2 | US$0 | Google Play, worldwide | Yes — HTTPS, anonymous for public repos | Yes — native Compose renderers | No, deliberately: a reader, not an IDE |
| GitHub Mobile | US$0 | Google Play and the App Store | No — it reads repositories hosted on GitHub | Only what GitHub itself renders, online | Edits files inside a pull request |
| Termux + git | US$0 | F-Droid or GitHub | Yes — the real git CLI | No — terminal text only | Yes, a full shell and any CLI editor |
| MGit 1.7.0 (2023) | US$0 | F-Droid only | Yes — clone, pull, push, HTTPS or SSH keys | No | No — its own listing says it ships no text editor |
Prices are for the download. GitHub Mobile’s capabilities follow your GitHub plan; Termux and MGit are both free software. MGit’s version and date are from its F-Droid listing.
Every figure here is read out of the shipping build or off a primary source listed at the foot of this page — nothing is rounded up for effect.
0.8.2, build 16, last reviewed on 27 August 2026.minSdk 30 — the API level Android 11 shipped with in 2020 — compiled and targeted against API 36.The primary documents behind the figures above, so you can confirm any of them without taking our word for it.
git-clone reference — the operation the app's clone button performs, in the words of the project that defines itminSdk names as its floorPage last reviewed 2026-08-27, against FoldRender 0.8.2.