diff

Visual two-column diff, JSON-aware with key-based alignment and date handling.

Paste two blobs, see what changed — JSON-aware, date-aware, everything local. USE CASES • Compare two API responses side-by-side while debugging, without piping them through a terminal or an online diff tool. • Track how a JSON payload evolves across a session — keep every intermediate version and jump back and forth from a dropdown. • Review config changes (YAML, .env, TOML pasted raw) with the same clarity as a code diff, before committing. • Spot which timestamps actually changed in a noisy response and grey them out in one click, instead of chasing microsecond drift by eye. HIGHLIGHTS • Two-column side-by-side view with line numbers, per-line and per-block apply arrows (« » to push a change across, ← → for a single line). • JSON auto-detect: when both sides parse, switches to canonical pretty-print, sorts keys by default, and surfaces structural stats (keys added/removed, value differences, type mismatches). • Smart alignment: within a changed block, keys are paired across sides by name (LCS on JSON keys), so the same field lines up even when surrounding lines are restructured. • Date-aware: ISO 8601 strings (2026-04-16T18:01:05.315420+02:00) and Unix timestamps are detected as atomic tokens. Toggle "ignore dates" to grey-out date-only differences. Intra-date highlighting isolates which parts actually changed (hour, minute, microseconds…). • Word-level highlighting with a noise filter: if too many runs of tokens differ, the whole line is shown as changed without fragmented sub-spans. • Raw mode: natural sort (so "item10" > "item9"), ignore whitespace. • Version system: click + to start a new version, pick any version per side from a dropdown, rename versions, compare across history. Nothing is duplicated — selecting the same version on both sides auto-shifts the other. • Edit / diff modes: editable textareas with live line numbers, or read-only rendered diff. Double-click any diff cell to jump back to edit with focus on that side. • No network, no analytics, no data ever leaves the browser. OPEN SOURCE Source on GitHub — https://github.com/Matthour/diff