FREE EXPANSION
Fly, land and restart a game you build in JavaScript.
$0.00Yours to keep
Free passkey account · No payment needed
Practice Packs
A collection to work through and keep. Free JavaScript project packs and deeper engineering challenges, with real tasks, hints and code you can run.
Free JavaScript expansions
200 new activities in each pack
FREE EXPANSION
Look up a ZIP code, display weather and handle failed requests.
$0.00Yours to keep
Free passkey account · No payment needed
FREE EXPANSION
Practice staging, commits, branches and safe recovery.
$0.00Yours to keep
Free passkey account · No payment needed
FREE EXPANSION
Build a task list with filters, completion and saved progress.
$0.00Yours to keep
Free passkey account · No payment needed
Engineering expansions
Keep the packs you buy
EXPANSION PACK
Recover uploads, reconcile payments and repair changing feeds.
Checking price…One-time purchase
Requires Web or higher
EXPANSION PACK
Handle buffers, journals and resource lifetimes in Go and Rust.
Checking price…One-time purchase
Requires Plus or higher
Owned packs stay in your library when you change plans. Your current membership determines which subjects you can practice.