MrEditor

Logs. CSVs. Exports, dumps, diffs. Text that arrived from somewhere else — so you don't get to choose its size, its encoding, or how badly it is formatted. MrEditor opens it, filters it, lines up its columns, compares it, fixes it, and saves it without ever leaving the file half-written.

That is also why there is no autocomplete and no LSP here: this is not for writing code, it is for finding out what happened and correcting it .

Japan's full corporate registry as CSV — 1.18 GiB, 5,816,535 rows — starts displaying in 52–60 ms (five runs). Excel opens the same file and stops at 1,048,576 rows , its hard limit, taking about 60 seconds and 2.24 GB to silently lose 4,767,959 rows. Numbers never opened it at all.

Size is not the trick, it is the floor: a 10 GB, 86,420,337-line log starts displaying in about 100 ms (ten runs: 97–107 ms), vmmap reports 0 bytes dirty for it, and jumping to the last line takes 0.1 ms . Nothing about the app changes as the file grows.

(All measured 2026-09-03 on the shipping 1.14.0 build, Apple Silicon. Ranges are what several runs actually produced, not the best one — see Performance for how to reproduce them.)

It started life as a fast read-only viewer (full-file search, filtered view / live grep, tail -f ). v0.4 makes the name literal : it edits and saves too.