Quarterly Practice Packs

New missions beyond the core curriculum. Choose a pack, or collect new releases with Drops Pass.

Each pack adds distinct problems around one engineering theme. Your membership provides the languages and tools; your pack stays in your library when you change plans.

Coming soon — 8 packs Continue practicing Compare plans Downloads and setup

2026-Q4

Boundary Conditions

Recover failed uploads, reconcile money, and repair live feeds without losing boundary data.

200 distinct practice itemsJavaScript · TypeScript

Exercises: 50
Code practice: 25
Challenges: 25
Gym problems: 100

25 Easy25 Medium25 Hard25 Pro

JavaScript: FreeTypeScript: Web or higher

Available to own

Purchase requires Web or higher.

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2026-Q4

Ownership at the Boundary

Hand off buffers, recover journals, publish snapshots, and shut down resources without breaking ownership.

200 distinct practice itemsGo · Rust

Exercises: 50
Code practice: 25
Challenges: 25
Gym problems: 100

25 Easy25 Medium25 Hard25 Pro

Go: Plus or higherRust: Plus or higher

Available to own

Purchase requires Plus or higher.

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Owned packs stay in your library when you change plans. Your current membership determines which subjects you can practice.

Coming soon

Planned engineering themes. Each release will follow the 200-item format, with focused practice leading into realistic debugging and harder problems.

Coming soon

Async Under Pressure

Race conditions, cancellation, retries, timeouts, concurrency limits, and duplicate requests.

JavaScript · TypeScript · Node

Coming soon

State That Behaves

Stale and derived state, effect cleanup, forms, optimistic updates, and accessible interactions.

React · Angular · TypeScript

Coming soon

APIs That Survive

Idempotency, authorization, rate limiting, webhooks, versioning, and partial failures.

Node · ASP.NET · PHP · Backend

Coming soon

SQL Beyond SELECT

Joins, window functions, transactions, indexes, query plans, migrations, and concurrent updates.

SQL · Backend

Coming soon

Python in Production

Iterators, generators, typing, context managers, file processing, exceptions, and testable pipelines.

Python

Coming soon

Memory and Machines

Pointers, allocation, buffers, object lifetime, RAII, binary layouts, and undefined behavior.

C · C++

Coming soon

Services in C#

LINQ, collections, async cancellation, disposal, dependency injection, middleware, and request handling.

C# · ASP.NET

Coming soon

Systems That Fail Gracefully

Queues, caching, backpressure, consistency, circuit breakers, recovery, and observability.

Architecture · Backend · Middleware and integration