File Diff
Compare two text files or PDFs. Line diff with inline character highlighting.
File A (original)
Drop file A
text · code · PDF
Click to browse, or paste files and links (Ctrl/⌘ + V)
File B (changed)
Drop file B
text · code · PDF
Click to browse, or paste files and links (Ctrl/⌘ + V)
About File Diff
Compare any two text-based files directly in your browser. Drop a file into slot A and slot B — the diff runs automatically. PDF files are supported: text is extracted using PDF.js before comparison. Changed lines show character-level inline highlighting. Long unchanged sections are collapsed for readability.
What file types can I diff?
Any plain text file — source code, JSON, YAML, Markdown, CSV, config files, etc. PDF files are also supported (text is extracted first).
Is there a file size limit?
The diff is capped at 3,000 lines per file. Beyond that, lines are truncated and a warning is shown.
Are my files uploaded?
No. Text extraction and diffing run entirely in your browser. Nothing is sent to a server.
How does the diff algorithm work?
It uses Longest Common Subsequence (LCS) with a typed array to find the minimal edit distance between two sets of lines.
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