Architecture diagrams and equations are the part of a README that usually degrades to quoted source on a phone. FoldRender renders them, from assets bundled inside the APK, with the rendering surface cut off from the network entirely. Here is how to get them on screen and how to confirm for yourself that nothing is being fetched.
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.
Clone the repository from the git panel, or use Open a file / Open a folder for something already on the phone. Then tap the Markdown file in the Files tab. Nothing has to be enabled: mermaid and math are part of the Markdown pipeline, not a setting.
A diagram is a fenced block tagged mermaid. Math is $…$ inline and $$…$$ as a block. These are the same conventions GitHub and Obsidian use, so an existing README needs no changes to render here.
Tapping a rendered diagram opens it full-screen with pinch zoom, which is the only way a wide sequence diagram is readable on a folded phone. A close control returns you to the document at the same scroll position.
Turn on airplane mode and reopen the document. The diagrams and equations still render. This is not a cache: mermaid and KaTeX, fonts included, are packaged in the APK's assets, the rendering WebView has blockNetworkLoads set, and its client returns a 403 for any URL that is not a bundled asset or a data URI. There is no configuration that would let it reach the network.
The share icon opens the Export sheet. Share as HTML writes one self-contained file with the KaTeX fonts, the mermaid output and every image inlined as data URIs — it opens on a machine that has never heard of mermaid. Print / Save as PDF and Share as PNG come from the same HTML, so all three match what was on screen.
Each math or diagram block gets its own sandboxed rendering island rather than the whole document being handed to a browser. The prose around it stays native Compose — native text selection, native theming, native scrolling.
Network access is refused by the WebView client, which returns a 403 for anything outside the bundled asset directory or a data URI, and independently by blockNetworkLoads on the WebView's settings. Either alone would do it; both is the point.
Diagrams and math sit in the same GFM Markdown the app already renders — tables with alignment, task lists, callouts written as > [!NOTE], footnotes, wiki links and front matter as a metadata header.
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.