What is the diff checker?
The Diff Checker compares two versions of text or code and highlights every insertion and deletion in color. Switch between line, word and character granularity, unified or side-by-side views, and ignore whitespace or case to hide noise. Free and entirely client-side: your text is never uploaded, logged or seen by anyone.
The GigAI Diff Checker is a desktop-grade text comparison tool that runs entirely in your browser. Drop two versions of anything: source code, JSON, a config file, a contract clause, a migration script or a paragraph of prose, and it highlights every insertion and deletion in color, the moment you stop typing. Switch granularity between line, word and character to zoom from 'which lines moved' down to 'which exact letters changed', and flip between a compact unified view and a true side-by-side split when you want the before and after aligned column-for-column. Noise-cancelling toggles let you ignore leading and trailing whitespace or ignore case, so a re-indent or a capitalisation change never masquerades as a real edit. A live counter tells you how many units were added and removed, you can copy the rendered diff or share a link that reopens both inputs, and full undo/redo plus real keyboard shortcuts keep you moving. Because the comparison happens locally with a battle-tested diff algorithm, your text (proprietary code, credentials, personal data, unreleased copy) is never uploaded, logged or seen by anyone. Close the tab and it's gone.
- Difficulty:
- Easy
- Typical time:
- ~15s
- Processing:
- 100% browser processing
Last updated
How to use the diff checker
- 1
Paste both versions
Put the original on the left and the changed version on the right, type, paste, drop a file onto either pane, or load the built-in sample to try it instantly.
- 2
Choose granularity & view
Pick line, word or character diff, then switch between unified (inline) and split (side-by-side) view depending on how much detail you want.
- 3
Filter the noise
Toggle Ignore whitespace and Ignore case to hide formatting-only or capitalisation-only differences and reveal just the meaningful edits.
- 4
Read, copy or share
Check the added/removed counts, copy the rendered diff, or share a link that reopens the tool with both inputs preloaded for a colleague.
What Diff Checker includes
Line, word or character diff
Switch granularity on the fly: line mode for 'which rows changed', word mode for edits inside a sentence, and character mode to pinpoint a single flipped letter or digit.
Unified or split view
Read a compact inline diff, or flip to a true side-by-side split that aligns the original and changed versions column-for-column so before and after line up.
Ignore whitespace & case
Suppress noise from re-indentation, trailing spaces or capitalisation so a formatting pass never shows up as a real change, see only the edits that matter.
Live added / removed counts
A running tally shows exactly how many lines, words or characters were inserted and deleted, updating the instant you stop typing. No Compare button to press.
Instant, even on big pastes
A debounced, cancellable engine keeps the tab responsive on large inputs, recomputing only the latest change so long documents diff smoothly.
100% in your browser
Both versions are compared on your device with a proven diff algorithm. No source code, config or personal text is ever uploaded, stored or logged.
Why use our diff checker
Spot the real change in seconds
Color-coded insertions and deletions turn 'these two files look different somewhere' into an exact, at-a-glance answer, without eyeballing line by line.
Cut review noise
Ignore-whitespace and ignore-case strip out reformatting and casing churn, so a code review or contract redline focuses only on substantive edits.
Zoom to the exact edit
Drop from line to word to character granularity to find the single toggled boolean, changed digit or swapped word behind a failing test or a broken config.
Private by design
Because everything runs locally, you can safely compare text containing secrets, PII, unreleased copy or proprietary code: none of it leaves your machine.
Built for the way you work
From quick one-off fixes to daily workflows, see how people put this tool to use.
- Developer
Review a code change without Git
Paste an old and new function or config side by side to see exactly which lines and tokens changed, ignoring whitespace so a reformat doesn't drown out the real edit.
- QA / SRE
Compare config across environments
Diff a staging config against production to catch the one flipped flag, changed host or missing key that explains why a deploy behaves differently.
- Writer / Editor
Redline a document revision
Drop two drafts in and use word-level diff to see every added, removed or reworded phrase between versions of copy, a contract or documentation.
- Data engineer
Verify an export or transform
Compare a data dump before and after a migration or cleanup to confirm only the intended rows and fields changed, down to the character.
Supported formats
Accepts TXT, Code, JSON, YAML and CSV, and produces Diff and TXT, all processed locally in your browser.
- TXT
- Code
- JSON
- YAML
- CSV
- Diff
- TXT
Frequently asked questions
Recommended tools
JSON Diff
Compare two JSON documents by structure, not text. Reordered keys and whitespace are ignored. You see added, removed and changed values by path with counts, all in your browser.
JSON Formatter
Format, validate and minify JSON in your browser with pinpoint error line + column, jump-to-error, key sorting and live editing: nothing is uploaded.
SQL Formatter
Format, beautify and minify SQL in your browser with a dialect picker (PostgreSQL, MySQL, T-SQL, BigQuery, Snowflake…), keyword-case control and custom indentation: nothing is uploaded.
YAML Formatter
Format, clean and re-indent YAML in your browser, or convert YAML ↔ JSON, with key sorting, flow/block style and the exact error line + column. Nothing is uploaded.
Barcode Generator
Generate scannable 1D barcodes (CODE128, EAN-13, UPC-A, CODE39, ITF-14, MSI, pharmacode and Codabar) live in your browser, with per-format validation and PNG or SVG export. Nothing is uploaded.
Base64 Decoder
Decode Base64 back to text or a file instantly: Unicode-safe, auto-detects URL-safe input, sniffs binary data and offers a download. Runs fully in your browser, nothing uploaded.
Common problems, solved
Hit a snag? Here are quick fixes for the issues people run into most.
Whitespace-only changes are cluttering the diff.
Turn on Ignore whitespace to collapse leading/trailing-space and indentation differences. If a reformat still shows up, switch to line mode first, then narrow to word mode once the big structural moves are clear.
The whole text shows as one giant change.
That usually means the two sides share almost no lines in common. Check you didn't paste the same version twice, or that line endings match. Try word or character mode to align the shared content more finely.
Character mode is slow on a very large paste.
Character-level diffing is the most expensive granularity. For big documents, start in line mode to locate the changed region, then copy just that region into a fresh compare for character detail.
A capitalisation change is flagged as an edit.
Enable Ignore case so 'Error' and 'error' are treated as identical. Combine it with Ignore whitespace to strip both casing and formatting noise in one pass.
Get the most out of it
Start in line mode to find which rows moved, then switch to word or character mode to see the exact edit inside them.
Turn on Ignore whitespace before reviewing code that was reformatted, so re-indentation doesn't hide the real change.
Use split view for aligned before/after reading, and unified view when you want a compact, copy-friendly inline diff.
Press Ctrl/Cmd+Enter to force a recompute and Ctrl/Cmd+Backspace to clear both panes and start fresh.
Share a link to send a colleague the exact two versions you're looking at, both inputs travel in the URL, nothing is uploaded.
What's new
Recent updates and improvements to the diff checker.
Initial release: live line/word/character diff, unified and split views, ignore-whitespace and ignore-case, added/removed counts, drag-drop import, undo/redo and shareable links.
Added keyboard shortcuts with an in-tool helper, a swap-sides action, and a curated sample so the empty state is one click from a real comparison.
Improved large-input performance with a cancellable debounced engine and refined split-view alignment for long, wrapped lines.
Keep exploring
Problems we solve
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Your privacy is built in
Both versions you paste are compared entirely in your browser with a client-side diff algorithm. They are never uploaded to any server. Nothing is stored, logged or transmitted, so you can safely diff text containing secrets, credentials, personal data or unreleased code. Share links encode the inputs in the URL itself. If the content is sensitive, copy the diff instead. Close the tab and every trace is gone.
- Runs in your browser
- No uploads
- Nothing stored
Ready to try the diff checker?
Free, private and instant. Diff Checker runs right in your browser.