Practice real development skills
Build practical programming habits with original exercises. Runnable challenges use the same Code Lab workspace and deterministic grading.
Backend API Essentials
Runnable nowPractice pagination, HTTP status handling and retry policies with deterministic function tests.
Normalize Pagination ParametersEasyDeveloper Skills15 minSolve →Classify HTTP Response CodesEasyDeveloper Skills12 minSolve →Calculate Retry BackoffMediumDeveloper Skills20 minSolve →Clamp ValueEasyDeveloper Skills12 minSolve →Normalize UsernameMediumDeveloper Skills25 minSolve →Inventory TotalEasyDeveloper Skills12 minSolve →Pagination Chunk CountMediumDeveloper Skills25 minSolve →Mask Email UsernameMediumDeveloper Skills25 minSolve →JavaScript & TypeScript
Runnable nowCore arrays, text normalization and utility functions. Multi-file TypeScript projects are planned.
Count Even ValuesEasyArrays12 minSolve →Deduplicate Preserving OrderMediumArrays25 minSolve →Running TotalsMediumArrays25 minSolve →Count VowelsEasyStrings12 minSolve →React & Next.js
PlannedNext: component debugging, hooks, rendering, server/client boundaries and accessibility.
Coming later — requires a project-aware evaluation system; no placeholder Run buttons.
Node.js Services
PlannedNext: Express middleware, validation, database queries and concurrency limits.
Coming later — requires a project-aware evaluation system; no placeholder Run buttons.
SQL & Data
PlannedNext: relational queries, grouping, joins and transaction scenarios.
Coming later — requires a project-aware evaluation system; no placeholder Run buttons.