How to open a JSON attachment on Android (WhatsApp, Telegram, email)
A colleague sends a config, a support team asks you to check an export, a friend shares a mod file. You tap the .json attachment on your Android phone, and nothing useful happens. Here’s what to do.
Short answer
Install a JSON viewer. Then tap the attachment and pick the viewer under Open with, or use Share and pick it there. If no app is offered, save the attachment to your phone first, then open it from inside the viewer (in Sonnet, Open file). Sonnet also shows up for attachments that chat apps label as generic files rather than JSON.
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Why tapping the attachment doesn’t work
Android decides which apps can open a file from a label the sending app attaches to it, called the MIME type. A well-behaved app labels a JSON file application/json. Plenty of chat and email apps just label it as generic data (application/octet-stream) or plain text. If none of your apps accept that label, you get “No app can open this file”. If the label is plain text, a basic viewer may show the whole file as one unreadable line.
Sonnet accepts both the JSON labels and the generic ones, so it’s usually offered either way. If a particular app still doesn’t offer it, the save-first route below always works.
The method that always works: save first, then open
- Save the attachment to your phone (steps for each app below).
- Open Sonnet and tap Open file.
- Find the file in the system picker, usually under Downloads or Recent, and tap it.
Opening a saved copy has another advantage: you can edit it and save your changes, which an attachment opened straight from a chat often won’t allow.
App by app
Menu names move around between app versions. These were the usual labels as of September 2026.
- Tap the document in the chat to download it, then tap again. Android offers the apps that can open it; choose Sonnet.
- To keep a copy, open the chat’s menu on the file and use Share → Files (or your file manager) to save it to Downloads.
- WhatsApp also keeps received documents in its own media folder, which on recent Android versions sits under
Android/media/com.whatsapp/WhatsApp/Media/WhatsApp Documents.
Telegram
- Tap the file to download it, then tap it again to choose an app.
- Use the file’s ⋮ menu → Save to Downloads to keep a copy you can open from Sonnet later.
Gmail and other email apps
- Tap the attachment. If Gmail can’t preview it, it offers to open it with another app.
- Use the download icon on the attachment to save it to Downloads, then open it from Sonnet.
Slack, Discord, Teams and browsers
- Download the file (it lands in Downloads), then tap the download notification or open it from Sonnet.
- Browsers sometimes display a JSON link as raw text instead of downloading it. Long-press the link and choose Download link.
Other things that go wrong
The file is a .zip
Exports often arrive zipped. Open the .zip in Files by Google or your phone’s file manager and choose Extract, then open the .json files inside one at a time.
The name ends in .json.txt
Some apps add .txt when saving. The contents are the same, so open it from inside Sonnet with Open file. You can also rename it in your file manager.
It opens but says “Invalid JSON”
Sonnet repairs missing or trailing commas and unclosed brackets on its own, so the problem is something else: another kind of syntax error, or a file that isn’t really JSON. For example, it might be an HTML error page someone saved as .json. See Invalid JSON: what the error means.
It’s very large
Sonnet opens files up to 20 MB for free. How to open a large JSON file covers bigger ones.
A word on privacy
Files people send each other for “can you take a look?” are often exactly the sensitive kind: exports with customer data, configs with API keys. Opening the file in an offline app keeps it on your phone. Pasting it into a website to format it doesn’t.
Open the next JSON attachment in one tap
Sonnet opens JSON from chats, email, your browser and your file manager as a clean, collapsible tree. Offline, no ads, no account. Free on Google Play, with an optional one-time Pro unlock for bigger files and search.
