What is the place of CodiMD in online trainings?

We’ve recently set up a test instance of CodiMD (the open-source version of HackMD) as way to test whether it was something useful for our community. With a transition to online training, I am wondering whether we should recommend it for some or all aspects of the training. The rich formatting content and features open up the possibility for some creative uses (share images, workflows, etc…). It does, however, bring a higher cognitive load for users. What is (if any) the place of CodiMD for online training events?

At a recent trainer meeting, @Denubis reported that the cognitive overload associated with this tool made it unmanageable in a workshop context.

I have seen HackMD used semi-successfully in a longer format workshop (non-Carpentries) but even in that context it was primarily Helpers and co-Instructors taking notes, with learners using it for reference ( though a few plucky ones pitched in. )

If we managed to fork CodiMD to take away the preview pane, I think it would be a better etherpad. The issue I had was that in an online workshop, when people were juggling screens and breakout rooms, trying to understand the markup-presentation dichotomy was too much for many of them.

In latter sessions (with a slightly different set of people), I switched to text on white background and “edit pane” only for the etherpad replacement (hackmd, technically.)

I’ll also add here that I’ve tested onlyoffice with a group of 20 and it failed entirely.

I see, when preparing for a workshop, that I have 3 options:

Google docs.

Example: https://docs.google.com/document/d/1f7lfzYyGOkrTyCI1_mO7mRrMaxpnYesQtW2rqi7YRBs/edit


  • It “just works”
  • Supports arbitrary people
  • Allows people to click my name to find my cursor


  • Google
  • No line numbers
  • Formatting can get in the way
  • Image inclusion might be distracting


  • Remember to not have an omni-document, but to add exercises as the workshop encounters them. Critical for docs because then the refrain is “go to the end”
  • Make sure headers are used, so the automatic table of contents (And a literal table of contents at the start) work
  • Focus on calling out exercise names rather than line numbers, and make sure they’re clickable.



  • Lowest barrier to entry
  • No formatting beyond simple style (bold/italic) and (now) headers
  • Has line numbers


  • I find the force reconnect frustrating
  • I’ve had it drop changes too many times during teaching demos
  • I find it hard to trust it.


  • Treat etherpad as mostly read-only


Example: https://hackmd.io/@denubis/SJdOeS2wI/edit


  • Stable
  • Markdown (I like it)
  • Line numbers
  • Sublime text key shortuts. (This is very much a pro only for me, but it makes me happy)


  • MARKDOWN (no one else likes it, cognitive load)
  • Too many options for viewing
  • No way to disable frills
  • Can’t support arbitrary URL-pads out of the box


  • Instruct learners to only be on edit view
  • Set colour scheme to coloured text on white
  • Do not mention markdown at all

Lessons learned:

I certainly wouldn’t use hackmd for an online workshop again. I might try it for a normal SWC workshop (instead of pre-alpha effectively DC) where I’m not really expecting them to write much collaboratively. The markdown is, on net, negative, but the colour coding has about the same impact as etherpad’s minimal formatting.

I will continue using docs for training demos, and probably for workshops. “Scroll to the end” plus high reliability is a better sell for me as lead instructor than “See line X” but low reliability.

I’m not sure what service I’d use for a train-the-trainers one though. I suspect that will be a long conversation with my co-trainer.