The Compare page

The main page (/) has two steps side by side: 1 · Select files and 2 · Output, with the Compare button and results below both.

Step 1 — Select files

Two drop tiles: the older file goes left, the newer right. Drag & drop, or click Browse device. The ✕ on a chosen file clears it. Both files must be the same kind (Word with Word, Excel with Excel) — a mixed pair is rejected immediately with a message, before you ever hit Compare.

The accepted extensions come from the server's actual capability (.docx, .docm, .xlsx), so the file picker never offers something the engines can't read.

Step 2 — Output

The panel adapts to the file kind you dropped — it only ever shows controls the active engine honours.

Header toggles

Report (on by default): prepends the comparison-report page (Word) or the Legend sheet (Excel copy) — every change listed. Untick for a clean output containing nothing but the compared content.
Verify (on by default): runs the round-trip verification after producing the output and stamps the result (✔/✖). Untick only for bulk jobs or a pathological document; there is deliberately no global off-switch.

Format

Word (.docx) — tracked changes: native Word revisions, accept/reject-able. How marks are displayed (colors, balloons) follows each viewer's Word settings.
Word (.docx) — colored (default for Word pairs): baked strikeout/underline in fixed colors. Two color pickers appear (insertion / deletion); the report page shows a color key with those exact colors.
Excel (.xlsx) — colored copy (Excel pairs only; their default): a colored review copy of the revised workbook. Three fill pickers appear (inserted / amber changed / deleted) — pre-set to your deployment's palette; cells fill with the exact color you pick, text auto-contrasted.

Engine options

Formatting (on by default): care about formatting-only changes. Word compare tracks them as "Formatted:" marks; Excel compare announces cells whose value stayed identical but whose fill/font/borders changed. Untick to silently adopt the revised formatting — less noise when a document was merely re-styled.
Changed content only (off by default): include just the changed content, with every omission explicitly marked. What that means per output — changed print pages, changed paragraphs, hidden sheets — is in Understanding the outputs.

Profile

If your deployment configures profiles (e.g. State of New York), a dropdown appears on the step-2 heading row. A profile is a named bundle of extra extraction rules and assertions — you choose it; the tool never guesses. Leave it at "—" for the global checks only.

Compare and results

Compare enables once both files are chosen. While running it shows a spinner; when done:

the output downloads automatically;
a green box confirms it, with the duration and a ✔ Verified badge (hover it for what the verification claims);
a yellow box lists any fidelity warnings — things that couldn't be redlined faithfully and deserve a manual glance;
a red box explains any error in plain language (unsupported pair, a print area that can't be aligned, the server busy, …).

Change anything — a file, an option, the profile — and the previous results clear automatically. Adjust and compare again; nothing else resets.