Practice makes programmers

Learn to code online with our beginner-friendly platform. Your account is free while we're still in beta.

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Learning to code is easier than ever


Watch your programs run, line by line

Computers can perform billions of operations in a second, but with our platform you can slow them down to human speed. Run your programs line by line and see exactly what is happening at each step.


Understandable error messages

Error messages are known for being hard to understand. No longer! Our application has friendly messages for thousands of common and not-so-common programming errors.


Never get stuck

Hit a roadblock? With our comprehensive in-app documentation panel and Show me feature, you'll never get stuck on our lessons!


Lots of lessons

We believe the only way to master a skill is practice. We'll be adding new lessons all the time!

Programming is for everyone

  • Women hold only 22.5% of tech jobs
  • Black people hold 11.9% of US jobs, but only 4.7% of tech jobs
  • Women in tech make 92 cents for every dollar a white man makes
  • Black and Latina women in tech make 90 cents for every dollar a white man makes
US Census Bureau (2016), (2018)

The tech industry is biased toward white men. We want to see women and minorities have a proportional role in the industry.

More information

About us

Most of us are programmers who learned the hard way. We're writing a new programming education system so you don't have to. See our our About page.


What is programming anyway? How is it different from coding, hacking, or engineering? Read this document expaining our view on programming.

White paper

Interested in our philosophy about teaching programming? Read the white paper that lays out our ideas.