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It's about time.ย 

Markwhen is the offline-first, plain text calendar and planning app you've been waiting for.

Meridiem Editor

Start with when.

Markwhen is a file format (and editor) that brings when into the limelight. Usually time is just metadata on something else.

It's time we bring time to the forefront.

1. Import

2. Collaborate

3. Repeat

A platform for planners.

Get everyone on the same page by importing other markwhen and collaborating in realtime.

All you need is time.

Markwhen is more than just a timeline maker.

Journaling? โœ…

Keep track of what you did in the easiest way possible.

Blogging? โ˜‘๏ธ

is a blogging platform built on markwhen - write your blog with a single file.

Traveling? โœ”

Chart your route and add pictures after the adventure is over.


It's all just files - save 'em, move 'em, do what you want with them.

Built-in visualizations

Move beyond just the calendar to a timeline, gantt, or map view

Custom visualizations

Make your own views


Annotate when necessary

Recurring events

Simple syntax for repeating events when necessary

Realtime collaborative editing

Plan your trip/project/weekend together

Open source language

Permissively-licensed so you can do what you want with it

VS Code extension


Import other shared markwhen into your own


Coming soon

Send reminders and other email based on when events are scheduled

Markdown-style images


Grouping events is a built-in part of the language

Tags & filters

Add tags to events to allow for filtering & searching


Viewing and editing permissions

Specify who can view and edit your markwhen in markwhen itself


Re is a blogging platform that uses markwhen - have an entire blog with just one file