launchd jobs

On a Mac, cron still exists but launchd runs everything: it starts your agents when you log in and system daemons at boot, keeps them alive, and fires them on timers, file changes and sockets. Each job is a property list, and most of the ways to get one wrong — a command with spaces in one string, a ~ nobody expands, a schedule without a Minute that fires sixty times an hour — produce no error at all. This page writes the plist for you, or reads yours and says what it will actually do.

How to use it

Pick the kind of job at the top. An agent runs as you while you’re logged in (~/Library/LaunchAgents, or /Library/LaunchAgents for every user); a daemon runs at boot as root or a user you name (/Library/LaunchDaemons). Give it a reverse-DNS label.
Build: type the command, choose when it runs — at load, kept alive (always, until it succeeds, after a crash), every N seconds, or on calendar schedules — and where its output goes. The plain English summary, the checks and the plist update as you type. Download the plist, or copy it.
Explain a plist: paste a job (XML, JSON or old-style; open a binary one as a file) and say where it lives. You get a summary, every key explained, and checks: unknown or misspelt keys (RunAtLod, Weekdays), wrong types (<string>true</string>), relative programs that launchd won’t find on its short PATH, shell syntax in ProgramArguments, ~ in paths, decimal Umask values that were meant as octal, UserName in an agent, paths in privacy-protected folders, and more. Edit in the builder carries it over.
From crontab: paste lines from crontab -l. launchd takes one number per key, so ranges, lists and steps are multiplied out into an array of dictionaries; day-of-month and day-of-week stay an OR, as in cron. It also says what doesn’t carry over: @reboot becomes RunAtLoad, % in a command, MAILTO, CRON_TZ, and Quartz-style L, W and #.
Schedule & sleep: the next run times in your time zone, and what a night’s sleep does to them. StartCalendarInterval jobs that were due while the Mac slept run once on wake (several missed runs become one); StartInterval firings are just lost; cron skips them; nothing catches up after a shutdown.
launchctl: the commands to install, load (bootstrap), enable, run now (kickstart), inspect (print, blame), reload after an edit, stop, and remove the job — for an agent in gui/$UID, or a daemon in system with sudo — and the legacy load/unload equivalents. Below them, what the usual errors mean (Bootstrap failed: 5: Input/output error, exit code 78, 126/127).
Keys lists every launchd.plist key with what it does, deprecated ones last.

The page never talks to launchd; it only prints commands for you to run.

From and to the cron tool

The cron expression tool has a Send to launchd button for any five-field schedule: it opens here in From crontab with the schedule already in the builder. The other way, Open in the cron tool next to each converted line shows that schedule there. Linux’s equivalent of a launchd timer is a systemd timer — server config builds those. To look inside or convert any property list, use property lists and defaults.

Checked against

The key descriptions follow launchd.plist(5) and launchctl(1) from macOS 27. Every plist the builder writes passes plutil -lint (the tests generate a range of jobs and lint them). The cron conversion uses the same parser as the cron tool. Jobs were not loaded into a real launchd while building this page, so the behaviour notes (sleep coalescing, throttling, ownership rules) come from Apple’s documentation rather than from experiments.

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Any current browser.

Privacy

Everything happens in your browser. Nothing you paste or build is sent anywhere; the page loads no outside scripts.

Works with

How to use it

From and to the cron tool

Checked against

Browser support

Privacy