See what actually changed.
The file comparison that hides timestamps and numbers without any regex knowledge — and pairs renamed folders all by itself.
Two versions of the same file. Something is different — but what? Your eyes jump from line to line, and after thirty lines you are no longer sure whether you missed something. With folders it gets worse: two backups of the same project, hundreds of files, and you're supposed to say what differs.
There is no shortage of comparison tools. Most of them, however, will also report every changed timestamp, every incremented build number and every copyright year as a “difference” — and if you want those hidden, you're expected to write a regular expression.
MergeQaiPro does it differently.
Both versions sit side by side, every deviation marked in colour — line by line, and within a line even character by character. Whatever you see can be moved from one side to the other with a single click. Whatever you do not want to see, you click away from ready-made building blocks: timestamps, numbers, GUIDs, comments. Without writing a single line of regex.
Besides text, MergeQaiPro also compares folders, images and any file byte by byte. And it is free — no trial period, no locked features, no credit card.
Four ways to compare
Text, folders, images, raw data — when opening, MergeQaiPro decides from the file type which view makes sense.
Regular expressions — without regular expressions
Every comparison tool can hide lines by regex. That does assume, however, that you know regex. MergeQaiPro turns it around: you click the pattern together from ready-made building blocks.
Ready-made blocks
Timestamps, numbers, version numbers, GUIDs, IP and e-mail addresses, web addresses, Windows paths, comments. Click, fill in the parameter, done.
Live preview
Every rule shows immediately, on real lines from your file, what it matches. You see the result before applying it — no guessing, no trial and error.
A warning against self-sabotage
A rule drawn too wide ends up hiding everything and makes the comparison worthless. MergeQaiPro detects this and tells you, instead of letting you run into the void.
Errors in plain language
If an expression is invalid, the program states the reason in ordinary language — not as a parser error with a character offset.
Moved is not deleted and rewritten
When a block is sorted to a different place, an ordinary comparison raises the alarm twice: once in red for “deleted”, once in green for “inserted” — for something that is unchanged in substance. MergeQaiPro recognises such moves and colours them turquoise.
At a glance you can see what is genuinely new and what merely sits somewhere else. Especially when reordering configurations, translation tables or blocks of methods, this is the difference between “three real changes” and “eighty reported ones”.
Merging in both directions
Blocks travel from left to right or the other way with a click. You decide per block — not per file.
Character-precise within the line
On a changed line, it is not the whole line that gets coloured, but exactly the character that changed.
Filters for real differences
Whitespace, letter case, line endings, special characters: you decide what counts as a difference and what passes as mere formatting.
Renamed folders are recognised by their content
Project_2025 becomes Project_2026,
Pictures becomes Photos. To a name-based
comparison these are two different directories: one missing on the
left, one missing on the right — and you get to check by hand what
actually differs inside them.
MergeQaiPro pairs such directories by their content and treats them as the same one. The list then shows a single row carrying both names — and below it, the real differences.
- A status column shows per entry: left only, right only, identical, different
- Six ready-made exclusion templates — for
node_modules,.gitor build folders, for instance - Copying in both directions; you are asked before anything is overwritten
- Double-clicking a row opens the matching file comparison
Four views and a similarity in per cent
With images, a line comparison is useless. MergeQaiPro therefore contrasts them as images — as a slider, side by side, overlaid, or as a difference image with adjustable amplification.
On top of that comes a perceptual similarity: instead of counting pixels, the program weighs structure, brightness, colour and frequency content (DCT) and gives you a percentage. Two versions of the same photo at different compression levels are thus recognisable as “practically identical” — even though not a single pixel matches.
Three versions and byte by byte
Three-way comparison
Two edits of the same original, three columns: Left · Base · Right. You see who changed what — and where both touched the same spot.
Byte by byte / hex
For everything that isn't text: a hex view with differing bytes highlighted. If the files are identical, the program tells you so directly.
Register once, then download
MergeQaiPro is free. In return we ask you to register with your e-mail address — that way we can let you know about new versions. It takes less than a minute and requires no credit card.
Honestly: self-service
MergeQaiPro costs nothing — and therefore carries no personal support. We would rather say so up front than keep you waiting later. The documentation makes up for it: the manual explains every window and every switch, illustrated throughout.
Manual
Twelve chapters, from the first steps to every keyboard shortcut — illustrated throughout.
Open the manualFrequently asked questions
Answers on features, installation, privacy — and on what “free” actually means here.
To the FAQLooks familiar? That's deliberate.
MergeQaiPro is the diff/merge core from SynQaiPro — embedded there in a complete file toolkit: duplicate finder, bulk renaming, synchronisation between PC, external drive and cloud, secure deletion, file recovery. If you like the comparison, SynQaiPro is the next step.