Best JSON Viewer and Editor Apps for iPhone and Android

Short answer: for JSON on a phone, a dedicated viewer beats a text editor because it shows a collapsible tree, repairs errors and compares files. JSON Viewer and Editor does this on iPhone, iPad and Android; browser-based JSON formatters are the quick alternative when you are online.

We make JSON Viewer and Editor, so weigh our pick accordingly. The other options here are good at what they do, and we say where they fit better.

What to look for

Options

FAQ

How do I fix invalid JSON on a phone? Use a fixer for trailing commas, missing quotes and unquoted keys.

Can I convert JSON to CSV on iPhone? Yes, along with YAML and XML.

Download JSON Viewer and Editor on the App Store · Get it on Google Play for Android

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~/cosmovex/home.md · rendered with Markdown Editor & MD Viewer

A Markdown editor good enough to write its own homepage.

This page is a Markdown document. You're reading the rendered preview — press or hit if you don't believe it. That round trip — plain text in, a clean document out — is what Markdown Editor & MD Viewer does on your Android phone. Free, offline, no account.

markdown Live Server — 2 editors, 1 file
# Two cursors, one document
My phone is hosting this file over Wi-Fi,
and my desktop is ed
> nothing leaves the device — it's your Wi-Fi, your file
▶  Install free on Google Play★ 4.7 on Play · 10,000+ installs · free

## New in v1.5 — watch it work

✓Version History — every save snapshotted; browse and restore
✓Works offline — no account, no cloud — files stay on your device

## Just shipped

Both offline-first, both free to try.

NEWAspenote: Offline Voice to TextIt writes it down. On your phone.Runs Offline · Nothing Uploaded · Summary & Actions
NEWHostPilot: PHP Server & SQLTurn your phone into a web server.PHP 8.4 & SQLite · Stays Running · SQL Console

## The rest of the toolkit

One app per job. No 200 MB do-everything bloat.

AppJobRating
Markdown Editor & MD ViewerWrite and preview Markdown on mobile.4.7★ · 5K+installios
WebEva: Build Websites & CodeBuild websites from your phone.4.4★ · 5K+installios
PDF Viewer & Editor - AIEdit, convert & sign PDFs on mobile.4.9★ · 1K+installios
HTML Viewer & Editor - CodeView & edit HTML on mobile.4.6★ · 1K+installios
SQLite Editor & SQL LearnerManage SQLite databases on mobile.5.0★ · 1K+install
Python IDE - Offline CompilerWrite and run Python on your phone.4.1★ · 1K+install
Aspenote: Offline Voice to TextIt writes it down. On your phone.—install
HostPilot: PHP Server & SQLTurn your phone into a web server.—install
DevBuddy: Offline Dev ToolkitYour pocket developer toolkit.—installios
ShellPilot - Batch SSH ClientSSH terminal & SFTP on the go.— · 1K+installios
API Client -REST & HTTP TesterTest APIs anywhere, anytime.— · 500+installios
JSON Editor - Viewer & FormatView, edit & format JSON instantly.— · 500+installios
Java & Kotlin Compiler IDEWrite and run Java on your phone.4.4★ · 1K+install
XML Viewer & EditorView, edit & validate XML on mobile.— · 5K+installios
Open CSV — Viewer & EditorOpen and edit CSV files on mobile.— · 500+installios
JavaScript Editor — React IDERun JavaScript and React on your phone.— · 1K+install
Image to SVG Converter, ViewerConvert images to SVG and edit vectors on mobile.— · 1K+install
YAML / YML Viewer & EditorView, edit & validate YAML instantly.— · 500+install
Network Toolkit: WiFi IP ToolsNetwork utilities and diagnostic tools.— · 500+install
Code Editor - Text & NotepadEdit text files on mobile.— · 500+install
C / C++ Compiler IDECompile & run C and C++ on your phone.—install
Diagram Maker: Flow & ERDDraw flowcharts & ERDs on mobile.—install
QR Scanner & GeneratorScan codes with confidence—install
Zip Extractor — Unzip RAR 7ZOpen ZIP, RAR, and 7Z files—install
PromptCrate: AI Prompt ManagerYour personal AI prompt library—install

## Free web tools

Background RemoverSnapglowSQLite ViewerQueryDrill

## Questions, answered

Is there a free Markdown editor for Android?

Yes — Markdown Editor & MD Viewer is free on Google Play. It gives you a split-view editor with live preview, syntax highlighting, and HTML/PDF export, and it works fully offline with no account.

Can I edit Markdown from my phone on a desktop browser?

Markdown Editor & MD Viewer includes a Live Server: your phone hosts the document over Wi-Fi and you edit it from any desktop browser with two-way live sync. The file never leaves your device.

Can I make Mermaid diagrams on Android?

Yes — the built-in Mermaid Studio turns plain text into flowcharts, sequence and class diagrams, with pan/zoom and SVG export, right on your phone.

Can I turn Markdown into slides or a PDF on my phone?

Presentation Mode turns any Markdown document into a fullscreen slide deck, and export produces styled HTML or print-ready PDF — all generated on-device.

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