How to open a JSON file on Android

Someone sent you a .json file, or an app exported one to your Downloads, and your phone either refuses to open it or shows one unreadable line of text. Here is every practical way to read it — including the ones that aren’t ours.

Written by the developer of Sonnet · Last updated 13 September 2026

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Why Android won’t open a JSON file on its own

JSON is plain text, but Android ships no app that registers to open it. Tap a .json file in Files and you usually get “Can’t open file” or a list of apps that would show it as one long, unindented line. Minified JSON — the kind APIs and exports produce — has no line breaks at all, so even when a text viewer opens it, it is close to unreadable on a phone screen.

What you actually want is an app that parses the file and lays it out as a structure: objects and arrays you can fold, keys and values on their own lines.

Which app should you use?

It depends whether you want to read JSON or write code. A dedicated JSON viewer gives you the tree; a code editor gives you the raw text with syntax highlighting.

Ads and install counts as shown on each app’s own Google Play listing (US store), checked 13 September 2026. We have not benchmarked the other apps, so this table does not rank them — it lists what each one is for.

Pick a JSON viewer if…

you open JSON files to find out what is in them: an API response, an app export, a config someone shared. A collapsible tree lets you skip straight to the part you need, and search saves scrolling through thousands of lines.

Pick a code editor if…

you are already editing code on your phone and JSON is one of many file types. QuickEdit and Acode are good general editors; they just show JSON as text rather than as a structure.

Pick an online formatter if…

the data is not sensitive and you will never need it offline. Read the privacy section below first.

Step by step: open a JSON file on your phone

1. Install a JSON viewer. Any of the apps above; this guide uses Sonnet, which is free and has no ads.
2. Find the file. Open your file manager (Files by Google, or your phone maker’s own) and go to Downloads, or wherever the file was saved.
3. Tap it and choose Open with. Pick the JSON viewer. Tick “Always” if you want .json files to go there by default.
4. Or open it from inside the app. In Sonnet, tap Open file and pick it with the system file picker — useful when the file manager doesn’t offer the app.
5. From a chat or email attachment: tap the attachment, then use Share or Open with and choose the viewer. Sonnet accepts JSON shared from other apps.

If no app appears under “Open with”, the sending app may have labelled the file as generic data rather than JSON. Save it to your device first, then open it from inside the viewer app.

Why does my file say “invalid JSON”?

Real-world JSON is often almost-JSON: hand-written configs, snippets copied out of JavaScript, output from a tool that cuts corners. A strict parser rejects the whole file over one character. The usual culprits:

{
  name: "Ava",            // unquoted key
  "plan": 'pro',         // single quotes
  "total": 128.5,       // trailing comma
}

• Unquoted keys and single quotes — valid JavaScript, not valid JSON. Sonnet reads both anyway and shows you the tree.
• Trailing commas — a comma after the last item in an object or array. Sonnet removes it when the file opens and tells you it did; in a text editor, delete it by hand.
• Comments (// or /* */) — allowed in some config formats (JSONC) but not in JSON. Remove them, or use a viewer that says it supports JSONC.
• A missing comma between two items — the parser will point near the line after the gap. Sonnet adds the comma on open, and repairs unclosed brackets the same way.
• It isn’t one JSON document — log files often hold one JSON object per line (JSON Lines). Each line is valid; the file as a whole is not.

Is it safe to paste JSON into an online formatter?

Only if you would be happy for that data to be on someone else’s server. The JSON people inspect on their phones is disproportionately the sensitive kind: API responses with tokens, customer records, app configs with keys in them. A website can process that in your browser or send it to its backend, and from the outside you cannot tell which.

An offline app avoids the question entirely. Sonnet parses and renders files on the device and has no server that receives them.

Can you edit a JSON file on Android?

Yes. JSON viewers with editing let you change values in the tree and save; code editors let you edit the raw text. In Sonnet you tap a value to change it, add or delete fields in place, switch the code view between pretty-printed and minified, and save your work as a local draft.

Open your JSON file in Sonnet

A clean, collapsible tree for any JSON file, tap-to-edit, formatted or minified code view, and local drafts. Works offline, no ads, no account. Free on Google Play, with an optional one-time Pro unlock for bigger files.