How MergeGlass works

MergeGlass turns two text-based sources into an aligned comparison, a list of changed blocks, and a combined result you control. The file contents remain in the browser workspace.

Add the sources

Select files or paste text. In three-way mode, also add the common base that both versions started from. File APIs read the contents inside the browser.

Prepare the comparison

MergeGlass normalizes line endings and applies the options you select. JSON and YAML modes can parse and normalize structure; text mode preserves the line-oriented source.

Build aligned changes

The diff engine separates equal lines from additions, removals, and replacements, then adds word-level detail inside changed lines. Long unchanged regions can be collapsed.

Resolve each block

Keep Source A, Source B, or both. In three-way mode, changes that only one side made can be combined automatically while overlapping edits remain visible for review.

Inspect the result

The combined preview updates with each choice and counts unresolved blocks. Read the complete output; a text merge cannot determine whether the resulting behavior is correct.

Export and validate

Copy or download the combined text, or export a unified patch. Then use the parser, compiler, tests, schema, or application checks appropriate to the file.

Two-way comparison

When you have two versions

Two-way mode answers: what differs between A and B? It is suitable for drafts, backups, generated output, unrelated copies, or a direct before-and-after review. Every changed block needs a human decision when producing a combined file.

Three-way merge

When you also have the common base

Three-way mode answers: what did each side change from the same starting point? That extra context helps merge independent edits and isolates cases where both sides changed the same area differently.

What never happens automatically

MergeGlass does not execute code, connect to a repository, upload a project, infer business intent, deploy configuration, or certify that output is safe. It is a focused review aid. You remain responsible for backups, validation, testing, and the decision to use the combined result.

The application route does not load advertising code. Anonymous Umami measurements use controlled event names and exclude filenames, source text, merged content, patches, clipboard contents, and raw errors. See the privacy notice for the complete boundary.