Diff Checker

Compare two blocks of text or code. Line, word, and character-level diff with color-coded additions and deletions. Unified and split view.

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Diff Checker is coming soon. In the meantime, try the JSON → CSV converter, which has flattening built in.

How it works

Myers diff algorithm

Uses the Myers algorithm — the same used by Git — to compute the shortest edit script between the two inputs. This produces the minimum number of additions and deletions needed to transform the original into the modified text.

Three granularity levels

Line diff treats each line as a unit (like git diff). Word diff splits on word boundaries for inline changes. Character diff compares individual characters — useful for catching single-character typos invisible at line level.

Example

Comparing two versions of a JavaScript function

Input

function greet(name) {
  return "Hello, " + name;
}

Output

- function greet(name) {
-   return "Hello, " + name;
+ function greet(name, greeting = "Hello") {
+   return `${greeting}, ${name}!`;

Two lines removed (red), two lines added (green). The function signature and return statement both changed.

Frequently asked questions

Can I compare JSON files?

Yes. For the cleanest diff, pretty-print both JSON blocks first using the JSON Formatter so structural differences appear as line-level changes. Without formatting, a single-line JSON diff shows everything as one huge change.

Is my content uploaded?

No. The diff runs entirely in your browser using JavaScript. Nothing you paste is sent to any server.

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All conversions run in your browser — nothing is uploaded.

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