Every feature, at ten-gigabyte scale.
Caxton isn't a fast editor with a large-file mode bolted on — the huge file IS the design target. Everything below runs on memory-mapped I/O, a piece-table document model, and a tiered line index, and every number is measured and archived.
Open anything, instantly
Drag a 10 GB production log onto the Dock and it's scrollable, searchable, and editable before you let go of the mouse. Indexing streams in the background — 80.6 million lines in 19.5 s — and nothing waits for it. Memory footprint stays under 200 MB no matter the file size.
The real 10 GB benchmark log: 80,610,954 lines, syntax-colored, fully indexed.
- Open modes for the truly enormous — whole-file by default, byte-range slice and tail modes when you want them.
- Follow-tail — pin the view to a growing log; appends absorb about once a second with full scrollback, search, and filters.
- Single-line monsters — a 500 MB minified bundle on one line scrolls like a config file; find runs in 0.5 s.
Read the manual: Opening Large Files →
Find & Replace that keeps up
A byte-level scanning engine covers ten gigabytes in about a second — 1.61 million matches found, counted exactly, highlighted live. Replace All is a single pass with a single undo step: all 1.61M replacements in 1.7 s.
1,613,344 matches at 10 GB in 1.3 s — the counter is exact, not an estimate.
- Case, whole-word, ICU regex, and escape sequences (
\n,\t,\xHH,\uHHHH) for cross-line searches. - Live highlights that track your edits — change a found word and its highlight retires instantly.
- Count, Find All, Bookmark All, search history, and Find in Files across a folder.
Read the manual: Find & Replace →
Filter: grep you can scroll
Show only matching lines — with original line numbers, full editing, and the rest of the app still working. 80.6M lines filter in 1.3 s. Chain conditions with AND/OR and per-condition negate; save presets; extract every match to a new document.
160,846 ERROR lines out of 8 million, applied in about a quarter second.
Multi-condition chains live in the Filter Lines panel — the bar stays one line tall no matter how many you stack.
A CSV workbench, not a viewer
Delimited files get a real grid: frozen headers, typed columns, one-click sorting, in-place cell editing. Two million rows parse in 2.6 s and sort numerically in 8.2 s. Split, combine, extract, and dedupe columns without leaving the app.
2,000,000 rows × 12 columns. Click a header to sort; double-click a cell to edit.
Read the manual: CSV Workbench →
Editing at scale
Keystrokes apply in about a millisecond on a 10 GB document. Multi-cursor editing runs to 1,000 simultaneous carets — a keystroke across all of them lands in under 120 ms, as one undo step. Option-drag for rectangular selection.
Type once, edit everywhere. Selections merge, overlaps dedupe, undo is a single step.
Read the manual: Editing at Scale →
Navigation built for millions of lines
Bookmarks persist across sessions and re-anchor by content when the file changed on disk. Markers keep patterns highlighted in six colors. The command palette puts every menu item a few keystrokes away.
⇧⌘P — fuzzy-search every command and recent file.
Read the manual: Navigation & Bookmarks →
Split view, two themes, an honest status bar
⌘\ splits the window into two independent viewports of the same document. Dark and Light themes are hand-matched to the product's design, with System following macOS automatically.
One document, two places at once — highlights and edits mirror, scrolling doesn't.
Read the manual: View & Themes →
Your work survives everything
Atomic saves that can't half-write. A crash-recovery journal every 30 seconds that never touches your original file. Session restore with scroll positions. External-change watching that reloads clean files and protects dirty ones.
Read the manual: Sessions & Recovery →
Private and native
AppKit and Swift top to bottom — no Electron, no web view. Your files never leave your Mac: no upload, no cloud processing, no telemetry of any kind. The only network calls are the update check and license activation, both disclosed.