TRY AN IDEA
Free developer tools
Change an assumption, inspect the result, and connect what you observed to a lesson. These tools work without signup.
INTERACTIVE
Big-O growth explorer
Compare how common operation-count models grow as input size changes.
Open tool →INTERACTIVESQL practice and query-plan lab
Run real SQLite queries on a fresh sample database, inspect joins and compare an indexed query plan.
Open tool →INTERACTIVESystem-design capacity calculator
Make traffic, peak-load and storage assumptions visible before choosing an architecture.
Open tool →