File Formats

How format detection works

Diffract uses three detection methods in order:

1. File extension - over 100 extensions are mapped to a format.
2. Exact filename - files like Makefile, Dockerfile, .gitignore are recognised by name regardless of extension.
3. Content sniffing - if a file contains a null byte within the first 8 KB, it is treated as binary.

The detected format determines which comparison view opens.

Format table

Format	Extensions / Filenames	Comparison view
Plain text	.txt, .md, .csv, .log, .yaml, .yml, .json, .xml, .toml, .ini, .cfg, .conf, .env, and 80+ more	Text (line-by-line)
Source code	.js, .ts, .py, .rs, .go, .java, .c, .cpp, .h, .cs, .rb, .php, .swift, .kt, .dart, and more	Text (line-by-line)
Shell scripts	.sh, .bash, .zsh, .fish, .ps1	Text
Exact filenames	Makefile, Dockerfile, Vagrantfile, .gitignore, .gitattributes, .editorconfig	Text
Binary	Any file containing a null byte; .exe, .dll, .so, .dylib, .bin, .dat, .db	Hex dump
Archive	.zip, .tar.gz, .tgz, .jar	Archive tree Pro
Image	.png, .jpg, .jpeg, .gif, .bmp, .svg, .webp	Image comparison Pro
Excel	.xlsx	Spreadsheet grid Pro
Word	.docx	Formatted document Pro
PDF	.pdf	Page text comparison Pro

Encoding detection

For text files, Diffract tries the following encodings in order and uses the first one that produces valid output:

1. UTF-8
2. UTF-16 LE (with BOM)
3. UTF-16 BE (with BOM)
4. Latin-1 (ISO-8859-1) - accepted for any byte sequence

Overriding the text encoding

If Diffract picks the wrong text encoding for a file (garbled characters are a common sign), click the encoding label in the encoding bar at the bottom of the comparison view, then select the correct encoding from the dropdown. The available options are UTF-8, UTF-16 LE, UTF-16 BE, and Latin-1.

See Encoding & Line Endings for details.

Forcing a comparison type

Diffract's format detection is based on file extension and content. If a file is misidentified as binary when it is actually text (or vice versa), the most reliable workaround is to rename it with a recognised text extension (such as .txt) before opening it.