Add your STRINGS file
Drop one or more .strings files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
STRINGS to ARB
Converting a .strings font to .arb repackages the same glyphs and metrics for a different delivery target. Free, private, and validated — the file never leaves your browser.
Private for supported formats — processed in your browser
Runs on your deviceConvert supported files
Drop STRINGS files here
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.About converting Apple strings localization to Application Resource Bundle
Converting a .strings font to .arb repackages the same glyphs and metrics for a different delivery target. A .strings file is Apple's localization resource: a flat list of "key" = "value"; statements, one per translatable string, usually named Localizable.strings and stored inside a per-language .lproj directory. It is what NSLocalizedString and its SwiftUI equivalents look up at runtime.
An .arb file is an Application Resource Bundle: a JSON object in which each key maps to a translatable string, and keys prefixed with @ carry that string's metadata — its description, its placeholder types and their formatting. It is the localisation format Flutter's intl tooling generates from and compiles to typed Dart accessors. For this route the practical draw is metadata lives with the string, so translators get context without a separate file and iCU MessageFormat covers plurals and gender without extra entries — balanced against the @-key convention doubles the entry count and looks odd to anyone new to it, which is worth knowing before you commit a large batch.
Why convert STRINGS to ARB?
The practical trigger for this conversion is usually a mismatch: with .strings, no plural support at all — that requires a second file in a different format. Switching to .arb buys you metadata lives with the string, so translators get context without a separate file, which is why it is the better fit for localising a Flutter application through gen_l10n. Because the conversion runs locally, trying it costs nothing but a few seconds of compute on your own machine.
STRINGS vs ARB at a glance
| Aspect | Apple strings localization (.strings) | Application Resource Bundle (.arb) |
|---|---|---|
| Format type | Text-based — characters and structure, so there is no visual quality loss | Text-based — characters and structure, so there is no visual quality loss |
| How it stores data | each entry is `"key" = "value";` — the trailing semicolon is required, and both sides use C-style escapes | the document is a single JSON object; ordinary keys map to strings, and @-prefixed keys map to metadata objects for the key of the same name |
| Strongest at | localising an existing iOS, iPadOS or macOS application | localising a Flutter application through gen_l10n |
| Weak spot | no plural support at all — that requires a second file in a different format | the @-key convention doubles the entry count and looks odd to anyone new to it |
| Metadata | keys and translated values are preserved. Comments are not treated as structured notes, and plural rules cannot be represented — a catalog with plurals converted into .strings will lose the plural forms because the format has no way to hold them | keys and their translated values are preserved. @-prefixed metadata — descriptions, placeholder types and formats — and the @@locale marker are skipped rather than converted, because flat key-value targets have nowhere to put them |
Pick ARB as the output
Select .arb in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if ARB is selectable, the route is real and validated.
Convert on your device
Press Convert. The font tables are parsed and rewritten locally with fonteditor-core; glyph outlines, hinting, and kerning survive the trip.
Verify and download
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid ARB file. Outputs keep the original filename with the .arb extension.
STRINGS to ARB questions, answered
Will converting STRINGS to ARB lose quality?
There is no visual quality to lose — strings is text-oriented and arb is text-oriented, so the question is structural fidelity. Text, ordering, and basic structure are preserved; complex layout, embedded objects, and styling beyond the target's model are simplified.
Is it private to convert STRINGS files here?
Yes — the .strings file is processed inside your browser tab and never uploaded. The font tables are parsed and rewritten locally with fonteditor-core; glyph outlines, hinting, and kerning survive the trip. Close the tab and the file is gone from memory.
Where will the ARB file work?
Flutter's tooling reads ARB natively and the major translation platforms support it; elsewhere it is just JSON. Novus Convert flattens the bundle locally, skipping @-prefixed metadata keys so they do not appear as translatable entries, and converts to and from the other localization formats. Placeholder metadata and ICU plural structure are not representable in flat targets.
Will the ARB file be bigger or smaller than my STRINGS?
It depends on the content: the document is a single JSON object; ordinary keys map to strings, and @-prefixed keys map to metadata objects for the key of the same name. Convert one representative file first and compare before batch-processing a large set.
What happens to the metadata in my STRINGS file?
In .strings, keys and translated values are preserved. Comments are not treated as structured notes, and plural rules cannot be represented — a catalog with plurals converted into .strings will lose the plural forms because the format has no way to hold them. Re-encoding through the browser pipeline does not carry embedded metadata into the output, which doubles as a privacy scrub — check the exported file if you specifically need tags preserved.
Can I convert ARB back to STRINGS?
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .strings → .arb → .strings is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.