EncodingProof — Text Encoding & Line-Ending Preflight

EncodingProof is a read-only local browser utility for batch checking text-file encoding, BOM, line endings, and final-newline consistency before delivery, publishing, or import.

Catch problems such as:

- One UTF-8 file accidentally saved with a BOM

- CRLF files mixed into an LF-only package

- Mixed line endings inside a single file

- Missing final newlines

- Unexpected control characters

- Replacement characters after decoding

Checks include:

- UTF-8 / UTF-8 BOM

- Shift_JIS / CP932 heuristic detection

- UTF-16 LE / UTF-16 BE

- BOM presence

- LF / CRLF / CR

- Mixed line endings

- Final newline

- NUL bytes

- U+FFFD replacement characters

- Suspicious control characters

Choose an expected delivery format such as:

UTF-8 without BOM + LF + final newline required

EncodingProof then marks files as PASS, WARNING, or ERROR.

Useful for:

- CSV delivery

- Localization files

- Subtitle files

- Source code

- Configuration files

- Web projects

- Cross-platform handoff

- Batch text QA

Privacy & safety:

- Runs entirely locally

- No file uploads

- No external API

- Read-only: does not convert or overwrite source files

- No installation required

- English / Japanese UI

Note:

Encoding detection without a BOM is heuristic. Shift_JIS / CP932 auto-detection in particular should be treated as a preflight aid rather than absolute proof.

EncodingProof is intentionally a checker, not a converter.