Today I Learn Documents

My team at work has been using these “Today I Learned” documents for a while now. This is an explanation of what they are and why are they useful.

Also this is very diluted and extra simplified approach inspired by Zettelkasten method.


“If you learn something, write something.”

(probably me)

Think about the time you asked something or the last time you had a rubber ducking session; when you ask, you order your ideas to present them to someone else, and often in the process you find the answer. 

Similarly, when we learn something and we write it down, we confirm our learnings, and that creates a link in our memory (that's how memory works) and we create a new piece of knowledge in our brain with the extra benefit we can consult it later.

Other benefits

  • Makes it easier to share with others. 

  • Unloads it from your short-term memory.

  • Very likely you'll use it yourself again.


Name it how you'd use it

Create a document and put as the title the learning. It is very important to name it as how you would like to search for it, instead of what the actual content (so you can Ctrl + F easily) 

Example: Let’s say the learning was how to use duration literals (1h, 2m) in configuration files after reading this documentation.

An ideal title would be:

“Use Simple Duration literals in application.yml file”

Instead of: "External configuration / Properties conversion",  because the next time you need it you’ll search something about duration or literals, and not necessarily about properties conversion.

Keep it very short

This is not a substitute for "formal" documentation. Use screenshots if possible and describe the happy path. The intention is to trigger the knowledge you already have, not necessarily to be a comprehensive guide to something. Write a formal document for that. 

Don't worry about re-document the obvious. It might not be obvious to others.

Use your own words

Perhaps the most important part of this document is to use your own words, even if they are not perfect. You'll see when you're trying to word it properly if you need to double-check your facts. Also using your own words creates a deeper link.

Add references!

Remember the last time you did exhaustive research? You end up with dozens of open tabs. Then you solve your problem and close all of those tabs (or bookmarked them)? Well, save them! Write your learning and add a "Resources/References" section at the bottom. 


Every time you learn something. 

If you're going to explain something to someone, they might as well create a TIL with the learning. 

The next person can use it as a reference and is very likely that person will be you.


Create an index where that can easily be accessible to any team member, it could be a blog or an index in another document. 

Share it with the right audience.

Keep it low friction! We might be tempted to use complex classification but the easier they are to write the better.


  • Name it as you’ll want to find them

  • Keep them very short and add references at the bottom

  • Use your own words


Zettelkasten Note-Taking Method: Simply (YouTube video)

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