Vaibhav Somani

WebRTC is the browser stack for peer-to-peer audio, video, and data channels.

Module Federation lets one JavaScript build load modules from another build at runtime.

Traffic shifting is the capability that turns a service mesh from a fancy observability layer into a genuine deployment safety net.

Mental model: hydrate less of what you already rendered Partial hydration is the practice of server-rendering a page while hydrating only the parts that need client-side behavior.

Containment gives the browser boundaries CSS containment lets an element promise that some of its internals do not affect the outside world.

Background job queues are where the optimistic assumptions of synchronous code go to die.

Mental model: hydration is scheduling, not just attaching events Hydration turns server-rendered HTML into an interactive client tree.

Cold starts are the tax you pay for not running servers.

Cumulative Layout Shift measures unexpected visual movement.

Pod Disruption Budgets (PDBs) are one of the most misunderstood reliability primitives in Kubernetes.

Referential equality means two values are considered equal because they point to the same object, array, or function instance.

Why bloat exists at all To understand index bloat you first have to understand a design decision at the heart of PostgreSQL: MVCC, multi-version concurrency control.

Mental model Cache-Control tells caches how long and under what rules a response can be reused.

Backpressure is the mechanism that prevents a fast producer from overwhelming a slow consumer.

Shadow DOM is an encapsulation boundary for DOM and CSS.

What a prepared statement actually buys you Every SQL query the database receives goes through a pipeline before a single row is touched: it is parsed into a syntax tree, analyzed and rewritten (resolving table and column names, expanding views), and then…

Mental model: static HTML with targeted interactivity Islands architecture starts from the assumption that most of a page can be delivered as inert HTML.

Largest Contentful Paint measures when the largest visible content element in the viewport is painted.

CSS pixels are not device pixels Modern layout is full of fractions.

A failure that looks like everything else Connection pool exhaustion is one of the most common production incidents, and one of the most misdiagnosed.

Mental model: components can be a transport boundary Server Components move part of the component tree to the server.

The promise and the catch Read replicas are the standard first move for scaling reads.

Mental model HTTP/3 is HTTP semantics running over QUIC instead of TCP.

Why shard at all A single database node has a ceiling.

Memoization caches the result of a computation for a set of inputs.

AbortController is the web platform’s shared cancellation primitive.

The dual-write problem Almost every service that owns data also needs to tell the rest of the system when that data changes.

Custom elements are classes that the browser upgrades into real DOM behavior.

Most applications use a single data model for both writing and reading: the same tables, the same objects, the same schema serve commands that change data and queries that fetch it.

Mental model Priority Hints let developers nudge the browser’s internal fetch priority using fetchpriority.

For two decades, the standard advice for writing scalable Java servers has been: never block a thread, because threads are expensive, so wrap everything in thread pools and reactive callbacks.

Speculative prerendering loads and renders a likely future page before the user navigates to it.

Why aggregate, and why sample A single modern service can emit tens of thousands of log lines per second.

Mental model: send the shell before every dependency is done Traditional server-side rendering waits until the whole page’s data and HTML are ready, then sends one response.

IntersectionObserver answers a geometry question asynchronously IntersectionObserver tells you when a target intersects a root rectangle.

Garbage collection is the JVM feature most developers ignore until a production incident forces them to care.

The stale closure problem occurs when a function keeps references to values from an old render, old state transition, or old lexical scope and then runs later as if those values were current.

Streaming fetch response handling lets a page process bytes as they arrive instead of waiting for the entire response body.

Mental model preload, prefetch, and preconnect are resource hints, but they solve different timing problems. preload says “this resource is needed for the current navigation; start it earlier.” prefetch says “this may be needed for a future navigation; fe…

When a system grows beyond a single machine, the comfortable abstractions of in-process method calls break down.

Mental model: move the first decision closer to the user Edge rendering runs request-time rendering logic in geographically distributed runtimes near the user.

Web Components are most valuable at boundaries: design systems used across frameworks, embeddable widgets, long-lived platform components, and islands inside applications that change framework stacks over time.

What cardinality actually means In Prometheus, a single metric name is not one thing.

When a service needs to read or write large files, the choice between traditional stream-based I/O and memory-mapped files (mmap) can change throughput, latency, and memory behavior by an order of magnitude.

Concurrency is hard because two independent activities can touch the same data at the same time and corrupt it.

Priority inversion happens when high-priority work waits behind low-priority work.

Mental model In a monolith, a stack trace tells you the whole story of a request.

The distinction between macrotasks and microtasks explains many frontend timing bugs.

Mental model CORS preflight is the browser asking a server for permission before sending a cross-origin request that could have side effects or expose non-simple behavior.

Mental model In a distributed system, the dangerous failures are not the ones that crash a single service — they are the ones that cascade.