Add your PO file
Drop one or more .po 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.
PO to ARB
Converting a .po 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 PO 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 GNU gettext translation to Application Resource Bundle
Converting a .po font to .arb repackages the same glyphs and metrics for a different delivery target. A .po file is a GNU gettext Portable Object: a plain-text translation catalog in which each entry pairs a msgid — the original string, which doubles as its own key — with a msgstr holding the translation. It is the format most open-source software is translated in, and it is designed to be readable and diffable in a normal editor.
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 PO to ARB?
The practical trigger for this conversion is usually a mismatch: with .po, keying on source text means an English typo fix invalidates every translation of that string. 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.
PO vs ARB at a glance
| Aspect | GNU gettext translation (.po) | 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 | entries are blank-line-separated blocks of msgid and msgstr, each a sequence of C-style quoted strings that concatenate across lines | 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 | translating open-source software, where gettext is effectively the default | localising a Flutter application through gen_l10n |
| Weak spot | keying on source text means an English typo fix invalidates every translation of that string | the @-key convention doubles the entry count and looks odd to anyone new to it |
| Metadata | identifiers, source strings, translations and context are preserved. Header fields, translator comments, source references and flags such as fuzzy are not carried into formats that have nowhere to put them — converting a reviewed catalog to a mobile resource file loses the review state, not the translations | 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.
PO to ARB questions, answered
Will converting PO to ARB lose quality?
There is no visual quality to lose — po 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 PO files here?
Yes — the .po 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 PO?
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 PO file?
In .po, identifiers, source strings, translations and context are preserved. Header fields, translator comments, source references and flags such as fuzzy are not carried into formats that have nowhere to put them — converting a reviewed catalog to a mobile resource file loses the review state, not the translations. 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 PO?
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .po → .arb → .po is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.