Online Tool Store
Text Line Diff Merger
Merge two versions of a text into one, keeping every line unique to either side wrapped in Git-style conflict markers so nothing is silently lost.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Lines unique to A or B are both kept, marked inline; lines only in a conflicting overlap are flagged for manual review.
How the Text Line Diff Merger works
- Paste two versions of a text into the two panels.
- A line-level longest-common-subsequence diff aligns the shared lines between both versions.
- The merged result keeps every shared line once and wraps any lines unique to either version in conflict markers, so nothing from either side is silently dropped.
When this is useful
Handy when two people have independently edited the same document — meeting notes, a README, a config file — and you want to reconcile both sets of changes into one file without manually re-reading every line.
FAQ
What does "merge keeping changes from both" mean here?
Rather than picking a winner, the tool performs a union merge: every shared line is kept once, and every line unique to Version A or Version B is preserved in the output, wrapped in Git-style conflict markers so you can see exactly which side each block came from.
How are conflict markers used?
When A and B both have unique content in the same location, the tool wraps them like a Git merge conflict: <<<<<<< only in A, the A-only lines, =======, the B-only lines, then >>>>>>> only in B — familiar to anyone who has resolved a merge conflict before.
Does this replace `git merge` or a real 3-way merge?
No. This is a 2-way line diff/union merge with no common ancestor, so it can't distinguish "A added this" from "B deleted this" the way a proper 3-way merge with a base version can. Use it for quick text reconciliation, not for resolving real version-control conflicts.
How we compare
| Feature | Online Tool Store | git merge (3-way) | Manual copy-paste |
|---|---|---|---|
| No repo or common ancestor needed | ✓ | ✗ | ✓ |
| Never silently drops either side | ✓ | ✓ | ✗ |
For real source-controlled files with a shared history, always use `git merge` or your VCS's proper 3-way merge — this tool is for loose text without version history.