OpenAnyFile
What is a .arb file?
Application Resource Bundle is a data format developed by Google, first released in 2011. It is usually created by Flutter localization.
JSON with @-prefixed metadata keys; Flutter's gen-l10n turns these into Dart code.
File details
| Full name | Application Resource Bundle |
|---|---|
| Category | Data & science |
| MIME type | application/json |
| Signature (magic bytes) | 7B ({) |
| Developer | |
| Introduced | 2011 |
| Opens with | JSON viewer |
| Uploaded? | No — read locally in your browser |
How to open a .arb file
OpenAnyFile routes .arb files to its JSON viewer, which shows the data neatly formatted.
- Drop your .arb file on the box above, click it to choose the file, or paste it with Ctrl+V.
- The real format is detected from the file's first bytes — not just its name.
- The file opens in the JSON viewer.
- Use fullscreen for a closer look, check its checksums, or download it back unchanged.
What works — and what does not
Works
Viewing and inspecting: the data neatly formatted. Size, type, signature and checksums are always shown.
Does not work
Editing and saving back. OpenAnyFile is a viewer, not an editor — for changes you still need the original app.
Is it safe to open a .arb file online?
Here, yes — because nothing is uploaded. Most "online viewers" send your file to their server. OpenAnyFile reads it with your browser's File API and decodes it on your own device, so there is no copy anywhere else. You can check: open your browser's network tab while opening a file — no upload appears.
Questions about .arb files
Can I open a .arb file without installing software?
Yes. OpenAnyFile opens .arb files in your browser using its JSON viewer. You get the data neatly formatted, with nothing installed and no account.
How do I know a file is really a .arb file?
Check its first bytes instead of its name. A genuine ARB file begins with 7B ({). OpenAnyFile shows the detected type, so a renamed file is easy to spot.
Is my .arb file uploaded anywhere?
No. The file is read locally by your browser and never sent to a server — it even works offline once the page has loaded.
Does it work on phones?
Yes — on Android and iPhone, in any modern browser. You can also install OpenAnyFile as an app.
Related formats
Other formats from the same family:
Format facts checked and page updated on September 25, 2026.