Diff Checker

Compare two text snippets and see additions, deletions, and unchanged lines.

Runs 100% client-side
On this page4 sections

HOW TO USE

  1. 01Paste the original text in the left pane.
  2. 02Paste the modified version in the right pane.
  3. 03Click Compare to see a line-by-line diff with additions in green and deletions in red.
  4. 04Use Swap to flip the panes, or Clear to start over.

Try it

Original: {"name":"qa.codes","tools":["cypress"]} Modified: {"name":"qa.codes","tools":["cypress","playwright"]}

WHEN TO USE

Use this to compare two text snippets and see exactly what changed — useful for reviewing config file edits, comparing expected vs actual test output, checking template changes, or diffing two versions of a fixture file before committing. Unlike a git diff, this works on arbitrary text without needing a file or a repository. Use Swap to reverse the direction and confirm the inverse diff reads as expected.

WHAT BUGS THIS FINDS

  • Unexpected whitespace difference

    A test assertion fails because a trailing space or line-ending difference makes strings that look identical produce a mismatch — Diff Checker highlights the invisible difference at line level.

  • Unintended config line removal

    A configuration change accidentally removes a required line along with the intended ones — compare the before and after versions to confirm every red deletion was intentional before deploying.

  • Merge conflict residue

    A file merged with conflict markers still has <<<<<<< / ======= / >>>>>>> lines left in — pasting both sides of the conflict and diffing shows the exact divergence to resolve.

  • Template substitution gap

    A template-generated output differs from the expected fixture in unexpected ways — Diff shows whether the delta is in the substituted values or in the surrounding template structure.

QA USE CASES

01

Expected vs actual output comparison

Paste a test's expected output on the left and the actual output on the right to see precisely which lines differ, making the root cause of the assertion failure visible at a glance.

02

Config change review

Compare two versions of a CI config, environment file, or YAML fixture before committing — confirms only the intended lines changed and nothing was accidentally removed.

03

API response change detection

Paste the baseline response and the new response to see which fields were added, removed, or changed — faster than reading both blobs and less error-prone than text search.