Text Diff Online
Paste two versions of any text and see exactly what changed — side by side or as a unified git diff-style block. Runs in your browser, because the text you diff is usually private.
How to compare two texts online
Paste the original on the left and the changed version on the right. ToolChop runs a classic longest-common-subsequence (LCS) line diff — the same algorithm GNU diff uses — and renders the result either side by side (two columns) or unified (one column with + / − markers). Removed lines are red, added lines are green, unchanged lines are white. Toggle Ignore whitespace and Ignore case to hide cosmetic changes.
Why a local text diff matters
The text people compare is almost always private — production config files, customer records, contract drafts, redacted log lines, pre-publication legal copy. Uploading either side to a third-party diff tool is a needless leak. ToolChop runs the diff entirely in your browser, so the text never crosses the network. You can confirm in DevTools → Network that no request fires when you paste.
Side by side vs unified — which to pick
Use Side by side when you want to scan both versions in parallel — best when each side is long and you care about overall shape. Use Unified when you want a compact, copy-pasteable diff in the same format as git diff — best for PR descriptions, chat messages, or anywhere you need to share the result.
What you can do
- Side by side or unified view
- Ignore whitespace and ignore case toggles
- Per-line numbers on each side
- Added / removed / unchanged summary chips
- Swap original ↔ changed in one click
Frequently asked questions
How do I compare two texts online for free?
Paste the original on the left and the changed version on the right. Pick a view (Side by side or Unified). Red shows removals, green shows additions, white stays unchanged. Toggle Ignore whitespace and Ignore case if those should not count as changes. No account, no upload, no daily limit.
Does ToolChop send my text to a server?
No. The diff algorithm (a classic longest-common-subsequence) runs entirely in your browser. Your text never leaves your device — important when you are diffing production config files, customer records, redacted logs, or pre-publication legal copy.
Why is the privacy story for a diff tool important?
The text people compare is often sensitive: production environment configs, copies of contracts, customer support emails being edited, API responses being redacted. Uploading either side to a third-party diff tool is a needless leak. ToolChop runs the diff locally so the text never crosses the network.
What is the difference between Side by side and Unified view?
Side by side shows two columns, with removed lines on the left and added lines on the right — easy to scan when both versions are long. Unified collapses to one column with - / + line prefixes, the format git diff produces — easy to copy/paste into a PR description or chat.
What does 'Ignore whitespace' do?
Collapses any run of spaces or tabs to a single space and strips trailing whitespace before comparing. This hides indentation-only changes (reformatting, switching tabs to spaces) so you can focus on real content changes. The displayed text keeps its original whitespace — only the comparison is normalized.
What does 'Ignore case' do?
Compares lines as lowercase, so changing 'API' to 'api' will not show up as a change. Useful when diffing log lines where casing varies, or when the source you are comparing has inconsistent capitalization that does not affect meaning.
Is this a line-level or word-level diff?
Line-level. Every newline starts a new comparison unit. For most code, config, and JSON diffing, line-level is the right granularity — it matches what git diff and standard diff tools produce. For prose where changes happen mid-paragraph, paste each sentence on its own line first.
What algorithm does ToolChop use?
A classic longest-common-subsequence (LCS) diff on lines, the same algorithm that powers GNU diff. It finds the smallest set of additions and removals that turns the original into the changed version — so identical lines anywhere align correctly even when blocks are reordered.
Is there a size limit?
ToolChop's diff is comfortable up to a few thousand lines per side. The LCS algorithm is O(n × m), so 10,000-line vs 10,000-line will work but feel slow. For multi-megabyte log diffing, do that in a CLI tool.
Why does my JSON diff show the whole object as changed?
If your JSON is on one line, the diff treats it as one line and any change marks the whole thing. Pretty-print the JSON first (use our JSON Formatter), then diff — you will see exactly which keys or values changed.
Can I diff two URLs or two files?
Paste their contents into the boxes. ToolChop is text-only — for binary file diffing use a hex differ. For diffing two URLs, fetch both and paste the responses. There is no upload step.
Why use ToolChop instead of an online diff tool that uploads my text?
Privacy. The text people paste into diff tools is almost always private — config files, customer records, contract drafts, redacted log lines, internal documentation. ToolChop runs the diff entirely in your browser so the text never leaves your machine. You can confirm in DevTools → Network that no request fires when you paste.