Devices: iOS, with an Android version coming soon.
Cost: Free to download and access the first modules in each course, with in-app purchases required to complete some courses.
How is it of use to journalists? Coding, or at least a basic understanding of programming, is becoming an increasingly important skill for journalists to have in the newsroom.
Many editorial teams now work closely together with developers to create interactive storytelling experiences and new formats, so knowing what is possible and in what time frame makes communicating easier and collaborations more productive.
The training team at The Financial Times for example has been teaching journalists about APIs.
"This isn't something that's going to help journalists with core reporting, but it will make them far more sympathetic about the work that our developers do, which helps us produce something better for our readers," Lisa Pollack, head of new projects at the FT, told Journalism.co.uk in January.
Once you have completed all the free modules, you can pay a one-off fee of £2.29 to access the rest of the course for one programming language, or £4.49 to unlock the rest of the app.
Some modules can also be unlocked for free in exchange for a Twitter or Facebook post supporting the app.
There are other free resources for learning to code, such as Codecademy or CodeAvengers. But many are available on desktop rather than smartphones – which means you wouldn't be able to complete a couple of exercises on your daily commute.
One you've downloaded Lrn, you can use the app offline, so it still works if you're in areas with no phone signal or data connection, making it ideal for squeezing in a few lessons on your tube journey.
Other coding apps available on iOS are Udacity, TimeToCode, which at the moment only includes HTML lessons, and Swifty, which helps you learn Swift, Apple's programming language.
- Which resources are you using to learn to code? Let us know in the comments below or tweet us at @journalismnews.