Direct uploads are great because they keep file traffic away from your Rails dynos, but the default UX is opaque. I attach a Stimulus controller that listens for Active Storage’s direct-upload:* events and updates a progress bar. This keeps the markup

RecyclerView displays large datasets efficiently with view recycling. I create a ViewHolder to cache view references and an Adapter to bind data. DiffUtil calculates minimal updates using areItemsTheSame and areContentsTheSame callbacks, improving per

Combining global scopes with database views creates powerful data access patterns for multi-tenancy and security. Global scopes automatically filter all queries for a model—perfect for tenant isolation or active record filtering. I implement the Scope

In containerized environments, the Go runtime can benefit from knowing the memory budget. With Go 1.19+, debug.SetMemoryLimit lets you set a soft limit so the GC reacts more aggressively before the process gets killed by the OOM killer. I treat this a

Rayon makes data parallelism trivial: replace .iter() with .par_iter(), and your loop runs in parallel across all CPU cores. It uses a work-stealing scheduler to balance load automatically. I use rayon for CPU-bound tasks like image processing, data t

While JWT works well for user authentication, service-to-service communication often uses simpler API key authentication. I generate cryptographically random API keys using SecureRandom.hex(32) and store them hashed in the database, similar to passwor

Modals are accessibility traps—literally. Without focus management, keyboard users can tab into the page behind the modal and get lost. I trap focus within the dialog while it’s open, restore focus to the trigger on close, and support Escape to dismis

CompletableFuture enables non-blocking asynchronous programming in Java. I use supplyAsync() to run tasks in thread pools and thenApply() to chain transformations. thenCompose() flattens nested futures, while thenCombine() merges independent futures.

WorkManager schedules deferrable, guaranteed background work. I create Worker or CoroutineWorker subclasses with doWork() method. Constraints specify when work runs—network type, charging status, battery level. One-time requests use OneTimeWorkRequest

The log crate provides logging macros (error!, warn!, info!, debug!, trace!) that are backend-agnostic. Libraries use log, and applications choose the backend (env_logger, simple_logger, or tracing). This decouples logging from the implementation. I u

Query debugging identifies performance and correctness issues. I use EXPLAIN ANALYZE to understand execution plans. Slow query logs reveal problematic queries. pgstatstatements tracks query statistics. Understanding sequential scans vs index scans hel

Sometimes you want a quick diagnostic without wiring a full metrics stack. expvar exposes variables at /debug/vars in a standard JSON format. I use it for a handful of counters like “requeststotal” and “jobsfailed” when I’m bootstrapping a service or