Value AdditionFree single-language check
A small check before a multilingual release

Find the broken bits.
Keep the translation yours.

Compare your source with a language file. Find missing keys, changed types and broken placeholders before they reach your interface.

Runs in this browser. No uploads to a server. No sign-in. No automatic saving.

1. Add your files

One source + one target; 1 MiB each. Nested JSON objects/arrays or flat key,value CSV.

Pasted source: source.json
Pasted target: target.json

2. Choose checks

Key/type checks and unsupported-syntax warnings always run. Digit differences can be valid changes in number style, dates or grammar. Text expansion does not prove screen fit.

What this check can—and cannot—tell you

Supported here

  • JSON objects and arrays; paths use JSON Pointer escaping, so a slash in a key stays distinct.
  • Flat CSV with exactly key,value headers, quoted commas/newlines and UTF-8 text.
  • Simple {name}, {0}, {{name}} and common printf tokens such as %s, %d, %1$s, %.2f.
  • Duplicate keys rejected. Input files stay unchanged.

Still needs your review

  • Not a translator, grammar checker or release certification.
  • ICU plural/select, custom placeholders, dynamic printf widths/precision and app-specific syntax need their own validator.
  • No XLIFF, PO, XML, YAML or CSV schema beyond key,value.
  • JSON nesting limited to 50 levels and 50,000 values per file. Do not use production secrets.

Check a release, not just one language.

The offline Batch Edition adds up to 20 target files, 5 MiB per file, reusable rules and a ZIP with separate language reports. Single-language checks stay free.

Batch Edition is being prepared. No payment button is connected here.