Feed - Trevor I. Lasn, Building 0xinsider

AEO and GEO for AI Overviews, ChatGPT, Claude, Gemini, and Perplexity 🔗

What Answer Engine Optimization and Generative Engine Optimization mean, and how to get your site cited by AI Overviews, ChatGPT, Claude, Perplexity, [...]

Why I Chose Rust for 0xInsider 🔗

No QA team. No on-call rotation. One person, one binary, one financial product. The compiler is my entire engineering org. [...]

Prediction Markets Broke My Brain About Probability 🔗

A year of watching people bet real money on outcomes changed how I think about everything. [...]

How I Use Vercel BotID to Stop Bots on Auth Endpoints 🔗

BotID verifies browser challenges before proxying to the backend. Here's how I set it up in Next.js 16. [...]

Google Search Console MCP for Claude Code 🔗

Pull GSC data into Claude Code to find CTR problems, indexing bugs, and keyword gaps — then fix them in the same conversation. [...]

I Built 0xInsider.com — a Whale Trade Tracker for Prediction Markets 🔗

Every large trade on Polymarket and Kalshi, the second it happens. Currently in beta — join the Discord for early access. [...]

AI Agents Explained 🔗

What AI agents are, how the agent loop works, and why they're different from chatbots. [...]

How Prediction Market Arbitrage Works (Polymarket, Kalshi) 🔗

Buy YES and NO for less than a dollar. One of them pays out a dollar. Keep the difference. [...]

Building Custom MCP Servers with Next.js and mcp-handler 🔗

How to build a MCP server that works with Claude Code, Gemini CLI, Cursor, and more. [...]

CSS :interest-source and :interest-target Pseudo-Classes 🔗

Style connected UI elements with CSS pseudo-classes that respond to user interest. Interactive examples showing tooltips, forms, and navigation withou [...]

::details-content: style expandable content without wrapper divs 🔗

The ::details-content pseudo-element lets you style the expandable content of details elements separately from the summary, no divs needed. [...]

View Transitions API: Smooth animations between DOM states 🔗

Create animated transitions between different states of your app without complex animation libraries. [...]

Chrome DevTools MCP: Let Your AI Agent Debug Your App 🔗

Give your AI agent access to your running application. They can see errors, inspect the network tab, check the DOM, and debug issues while you work. [...]

Claude Code Superpowers: How to Add Skills That Plan Before Coding 🔗

Superpowers is an MCP plugin for Claude Code that enforces planning, TDD, and debugging workflows. Setup guide with real examples. [...]

Lighthouse CI: Catch Performance Regressions Before They Ship 🔗

Lighthouse CI fails your builds when performance drops. I run it on every pull request. [...]

Next.js DevTools MCP: Your Development Server Just Got Smarter 🔗

The Next.js DevTools MCP connects Claude and Cursor to your running dev server. I use it every day. [...]

Context7 MCP: Stop LLM Hallucinations with Live Docs 🔗

Context7 MCP server pulls version-specific library docs into Claude Code, Cursor, and other AI editors. Setup guide and how it works. [...]

IndexNow: Get Pages Indexed in Minutes, Not Weeks 🔗

Set up IndexNow to notify Bing, DuckDuckGo, ChatGPT, and Perplexity the moment you publish. Free protocol, 5-minute setup. [...]

What's New in Next.js 16: Every Change Explained 🔗

Complete guide to Next.js 16 — async params, Turbopack default, stable caching APIs, and how to upgrade. With code examples. [...]

Original work is now an endangered species 🔗

When everything looks the same, being different becomes valuable again [...]

Now is the best time to break into tech 🔗

With AI tooling, a developer with 1 year of experience can match the output of someone with 10 years. The playing field has never been more level. [...]

Is it even worth learning to code? 🔗

With AI tools like Claude Code, Cursor, GitHub Copilot, OpenAI Codex, and Lovable, is learning to code still valuable? [...]

Anthropic's Sequential Thinking MCP 🔗

Ever wished your AI agent would slow down and think things through? This MCP server does exactly that [...]

NPQ: Open source CLI tool that audits and protects your npm installs from malicious packages 🔗

A CLI tool that checks packages for security issues and social engineering attacks before they hit your project [...]

Google's AI distribution advantage 🔗

While everyone debates models and features, Google owns the distribution channels that make AI stick [...]

How JavaScript Was Written Back In the Day 🔗

Have you ever been curious how JavaScript was written back in the day? I was, so I dug into some of the early frameworks and libraries to see what I c [...]

JavaScript compile hints: what they are and when to use them 🔗

V8's compile hints let you control which JavaScript gets compiled immediately during page load [...]

Error.isError(): A Better Way to Check Error Types in JavaScript 🔗

Why the new Error.isError() method solves important cross-realm issues and provides more reliable error identification than instanceof [...]

Robust Data Fetching Architecture For Complex React/Next.js Apps 🔗

How I use the 'Three Layers of Data' architecture pattern for React and Next.js apps to avoid common pitfalls, tech debt, and improve performance [...]

Float16Array in JavaScript 🔗

Understanding the new 16-bit floating point array in JavaScript [...]

Understanding Agent2Agent (A2A): A Protocol for LLM Communication 🔗

An exploration of Google's new open protocol that enables different AI systems to exchange information and collaborate [...]

Why I Value Firebreak Sprints for Managing Technical Debt 🔗

How scheduled developer freedom weeks can revolutionize your codebase and team morale [...]

CVE-2025-29927 - Next.js Middleware Bypass Explained In Simple Terms 🔗

The vulnerability skips Next.js middleware security checks by adding a single HTTP header [...]

The 5:1 Rule: Effective Performance Reviews For High-Performing Teams 🔗

Research reveals the ideal ratio of positive to negative feedback within high performing teams [...]

Intl.DurationFormat: Format Time Durations with Locale Support 🔗

Stop writing manual duration formatting code. Instead, leverage the new powerful Intl.DurationFormat API for internationalized time displays [...]

Open-source is where dreams go to die 🔗

Work for free and in return watch your passion get crushed by entitled users who are never satisfied [...]

Don't bullshit 🔗

Be the authentic voice in a world of manufactured personas [...]

Keep Your Node.js Apps Secure with `npx is-my-node-vulnerable` 🔗

This package compares your Node.js version against the Node.js Security Database, providing immediate feedback about potential security risks. [...]

Native Popover Element with HTML 🔗

Create overlays and dropdowns easily with the native HTML popover API [...]

WeakRefs in JavaScript: Explained In Simple Terms 🔗

Understanding how WeakRef helps manage memory in JavaScript [...]

Honey Quietly Hijacked Creator Revenue Through Affiliate Link Switching 🔗

Honey's controversial affiliate link practices and what it teaches us about Silicon Valley's ethics [...]

Node.js AsyncLocalStorage: Pass Context Without Prop Drilling 🔗

Use AsyncLocalStorage to carry request IDs, user context, and tracing data through async calls without passing them as arguments. [...]

CSS scrollbar-width and scrollbar-gutter Explained 🔗

Use scrollbar-width to thin or hide scrollbars and scrollbar-gutter to prevent layout shift. Browser support, examples, and gotchas. [...]

Add Auth to Astro 5 with Clerk in 5 Minutes 🔗

The simplest setup for adding Clerk authentication to your Astro project, with minimal code [...]

CSS ::target-text for Text Highlighting 🔗

A look at how browsers can highlight text fragments using CSS ::target-text, making text sharing and navigation more user-friendly [...]

align-content: The Simplest Way to Center Content with CSS 🔗

Finally, we can center things in block layouts without flexbox gymnastics [...]

Form Validation That Doesn't Annoy Users: CSS :user-valid and :user-invalid 🔗

The new pseudo-classes :user-valid and :user-invalid give us a smarter way to style form validation states based on user interaction [...]

HTML Details Element: The Native Accordion You're Not Using 🔗

Discover how the HTML details element can replace your JavaScript accordions and why it might be better than your current solution [...]

Tattoos Won't Break Your Tech Career 🔗

Building a tech career with a sword tattooed on my neck [...]

navigator.clipboard - The Asynchronous Clipboard API in JavaScript 🔗

Copy and paste text, images, and files using the new navigator.clipboard API [...]

CSS @supports: Write Future-Proof CSS 🔗

Detect CSS feature support and provide smart fallbacks with @supports [...]

CSS Supports Nesting Now 🔗

CSS nesting is finally supported in all major browsers. Write cleaner, organized stylesheets without Sass or Less [...]

CSS content-visibility: The Web Performance Boost You Might Be Missing 🔗

The content-visibility CSS property delays rendering an element, including layout and painting, until it is needed [...]

CSS :has() - The Parent Selector We've Always Wanted 🔗

Transform your CSS with :has(), the game-changing selector that finally lets us style elements based on their children. [...]

link rel='modulepreload': Optimize JavaScript Module Loading 🔗

The rel='modulepreload' indicates that a module script should be fetched, parsed, and compiled preemptively, and stored for later execution [...]

LH and RLH: The CSS Units That Make Vertical Spacing Easy 🔗

Exploring new CSS line-height units that eliminate guesswork from vertical rhythm [...]

The HTML Native Search Element 🔗

The search HTML element is a container that represents the parts of the web page with search functionality [...]

Web Performance API: Measure What Matters 🔗

From slow to fast: Using JavaScript's Performance API to optimize web apps [...]

HTTP CONNECT: Building Secure Tunnels Through Proxies 🔗

Understand how HTTP CONNECT enables HTTPS traffic through proxies [...]

Preloading Responsive Images 🔗

How to properly preload responsive images to improve initial page load [...]

You Don't Own Your Social Media Accounts 🔗

Social platforms promise exposure but quietly hold your audience hostage [...]

Working with JavaScript's Scheduler API 🔗

Learn how to prioritize and control task execution in JavaScript using the new Scheduler API for better performance and user experience [...]

WebAssembly (Wasm): When (and When Not) to Use It 🔗

Understanding the real use cases for WebAssembly beyond the performance hype [...]

The Fight to Free JavaScript from Oracle's Control 🔗

The creator of JavaScript and Node.js are challenging Oracle's control over the JavaScript name [...]

Recursion Explained In Simple Terms 🔗

Understanding recursion through real examples - why functions call themselves and when to use them [...]

Node.js Corepack: Version Control for Package Managers 🔗

Manage yarn and pnpm versions consistently across your team [...]

Can OSSPledge Fix Open Source Sustainability? 🔗

The Open Source Pledge aims to address open source sustainability challenges by encouraging companies to pay $2,000 per developer per year [...]

JavaScript Sets and Maps: Beyond Arrays and Objects 🔗

How to handle unique values and key-value pairs properly without type coercion and performance issues [...]

Precise Decimal Math in JavaScript with Fraction.js 🔗

How to handle exact decimal calculations in JavaScript when floating-point precision isn't good enough [...]

Exploring JavaScript Symbols 🔗

Deep dive into JavaScript Symbols - what they are, why they matter, and how to use them effectively [...]

Ghost Jobs Should Be Illegal 🔗

How fake job postings became a systemic problem in tech recruiting [...]

Can Scrum Be Salvaged? 🔗

Scrum is failing engineering teams and what it's actually costing us [...]

Understanding Bitwise Shifts in JavaScript: << and >> 🔗

A practical guide to left and right shift operators in JavaScript [...]

JavaScript Import Attributes (ES2025) 🔗

Understanding the new import attributes syntax and why we can't rely on file extensions alone [...]

Promise.try: Unified Error Handling for Sync and Async JavaScript Code (ES2025) 🔗

Stop mixing try/catch with Promise chains - JavaScript's new Promise.try handles return values, Promises, and errors uniformly [...]

JavaScript's &&= Operator: Understanding Logical AND Assignment 🔗

Use the &&= operator to safely update truthy values while preserving falsy states [...]

JavaScript's ??= Operator: Default Values Made Simple 🔗

A guide to using ??= in JavaScript to handle null and undefined values elegantly [...]

When Will We Have Our First AI CEO? 🔗

Welcome to the future of corporate leadership. It's efficient, profitable, and utterly inhuman [...]

The Monday Morning Test to Measure Engineering Team Health 🔗

Why the first day back can reveal everything about your engineering team's health [...]

Pkl: Apple's New Configuration Language That Could Replace JSON and YAML 🔗

A deep dive into Pkl, Apple's configuration language that aims to replace JSON and YAML [...]

No, Quantum Computers Won't Break All Encryption 🔗

Symmetric encryption algorithms like Advanced Encryption Standard (AES) are largely quantum-resistant already [...]

Introducing the Legendary Programmer Hall of Fame 🔗

Meet the innovators who laid the foundation for modern computing. Their contributions span decades, creating the tools and concepts developers use eve [...]

What is the JavaScript Pipeline Operator |> 🔗

A deep dive into how pipeline operators can make your code more readable and maintainable [...]

Why localStorage Is Unsafe for Tokens and Secrets 🔗

localStorage is vulnerable to XSS and has no expiry or encryption. Learn why httpOnly cookies and sessionStorage are safer for auth tokens. [...]

JavaScript Truthy and Falsy Values: Complete Reference 🔗

All 8 falsy values in JavaScript explained with examples. Common pitfalls with 0, empty strings, NaN, and how type coercion actually works. [...]

JavaScript Operators: '||' vs '&&' vs '??' 🔗

Master JavaScript logical operators with practical examples and best practices [...]

Inside the CSS Engine: CSSOM Explained 🔗

A deep dive into how browsers parse and manipulate CSS, its impact on web performance, and why it matters [...]

How to Land Your First Tech Job 🔗

A developer's guide to tech interviews - from someone who sits on both sides of the table [...]

Why Anthropic (Claude AI) Uses 'Member of Technical Staff' for All Engineers (Including Co-founders) 🔗

Inside Anthropic's unique approach to preventing talent poaching and maintaining organizational equality [...]

Offload Your Third Party Scripts With Cloudflare Zaraz 🔗

How I used Cloudflare Zaraz to offload third party scripts and improve my website performance. [...]

SecretLint — A Linter for Preventing Committing Credentials 🔗

A guide to catching and preventing credential leaks in your code using Secretlint [...]

Repopack (now Repomix): Pack Your Entire Repository Into A Single File 🔗

A tool that packages your code to easily share with LLM models. [...]

Software Engineer Titles Have (Almost) Lost All Their Meaning 🔗

Examining the Devaluation of Software Engineer Titles and Its Impact on Tech Industry Integrity [...]

Optimize Your Astro Site's <head> with astro-capo 🔗

Automatically improve your Astro site's performance using astro-capo [...]

How To Implement Content Security Policy (CSP) Headers For Astro 🔗

Content Security Policy (CSP) acts like a shield against XSS attacks. These attacks are sneaky - they trick your browser into running malicious code b [...]

VoidZero: Threat or Catalyst for Open Source JavaScript Tooling? 🔗

When Evan You announced VoidZero, I'll admit - I got excited. And a little nervous. [...]

Open Dyslexic Font: Improve Your Web Accessibility 🔗

How to implement the Open-Dyslexic font to enhance readability for users with dyslexia [...]

Small Habits, Big Impact 🔗

We're often focused on big innovations and breakthrough moments. But what if the real key to long-term success lies in the small, everyday actions we [...]

Is Age Really a Factor in Tech? 🔗

Silicon Valley has a reputation for youth worship. The 'move fast and break things' mentality often translates to a preference for younger, supposedly [...]

How to Launch Software Projects On Time and On Budget 🔗

Learn the art of scope management to keep your projects fixed in time and cost [...]

The Credit Vacuum 🔗

Being a developer sometimes feels like being the goalkeeper in a soccer match. You make a hundred great saves, and no one bats an eye. But let one bal [...]

A Company Is Not a Family. It's a Sports Team 🔗

'We're not just a company, we're a family!' It's a nice sentiment, sure. But it's also a load of crap. [...]

Cloudflare Study: 39% of Companies Losing Control of Their IT and Security Environment 🔗

New research reveals a shocking loss of control in corporate IT environments [...]

When Tasked with a Problem, Start with the Bigger Picture 🔗

When faced with a challenge, I always step back to see the whole picture first. It's like pausing a complex strategy game to study the map. You might [...]

Barnacle Strategy for Startups 🔗

As a founder, you're always on the lookout for smart ways to grow your startup without burning through your limited resources. That's where the barnac [...]

Micro Frontends: The LEGO Approach to Web Development 🔗

Explore the concept of micro frontends in web development, understand their benefits, and learn when this architectural approach is most effective for [...]

Google's Journey: From Search Engine to Tech Giant 🔗

Exploring the key innovations and strategies that transformed Google into a global technology leader [...]

Amazon's Rise to Tech Titan: A Story of Relentless Innovation 🔗

How Jeff Bezos' 'Day 1' philosophy turned an online bookstore into a global powerhouse [...]

Apple's Secret Sauce: The Untold Stories Behind Its Success 🔗

Diving deep into the lesser-known factors that propelled Apple from a garage startup to a tech titan [...]

What's the Number One Thing Holding Most People Back from Reaching Their Full Potential? 🔗

Discover the biggest obstacle to success in tech and learn how to overcome it [...]

Self-Taught Developer's Guide to Thriving in Tech 🔗

How to turn your non-traditional background into your biggest asset [...]

Make It Work First Before Optimizing 🔗

Users don't care how elegant your code is. They care if it solves their problem. [...]

Minimum Viable Documentation 🔗

How to create essential documentation that actually gets read and used. [...]

You Can Choose to Be Someone Who's Competent in Many Things, or Unbelievably Good at One Thing 🔗

Should you diversify your skills or specialize? [...]

Write Documentation Like a Journalist 🔗

Create comprehensive, engaging documentation by adopting journalistic techniques for research and storytelling [...]

Cloudflare's AI Content Control: Savior or Threat to the Open Web? 🔗

How Cloudflare's new AI management tools could revolutionize content creation, potentially reshaping the internet landscape for both website owners an [...]

Conway's Law: The Hidden Force Shaping Your Software Architecture 🔗

If you've ever wondered why your carefully planned software architecture ends up looking suspiciously like your org chart, you're not alone. Welcome t [...]

Internal Mobility 🔗

Just like a utility player on a sports team discovering their ideal position, internal mobility allows you to explore different areas of engineering a [...]

Outdated Docs Are Tech Debt 🔗

Teams often neglect to create good documentation. Code gets delivered, but updating the docs is treated as a secondary task, easily postponed—until it [...]

Weeks of Coding Can Save You Hours of Planning 🔗

Weeks of coding can save you hours of planning. It’s one of those sayings that’s been around forever, and for good reason—it’s a warning that still ho [...]

It's More Fun to Be Competent 🔗

Once you're competent, everything changes. You stop second-guessing yourself. You stop panicking every time you encounter a new problem. And you start [...]

Code Wins Arguments 🔗

How Meta and other companies use the 'code wins arguments' mindset to turn ideas into reality [...]

Take Your Writing Seriously 🔗

It’s not just about getting the message across; it’s about doing so in a way that’s easy for others to follow. Good writing shows respect for your tea [...]

Users Can Be Fired 🔗

Letting go of difficult or harmful users can be the key to maintaining the health and growth of your product [...]

A Great Product Doesn't Need Marketing 🔗

Great products speak for themselves, without the need for massive marketing campaigns [...]

Amazon's 'No Weasel Words' Rule 🔗

How Amazon's emphasis on eliminating weasel words leads to more precise, actionable communication and better decision-making [...]

The Real Cost of Meetings: What FAANG Companies Do Differently 🔗

Discover how FAANG companies like Amazon, Google, and Netflix reduce the hidden costs of meetings by embracing written communication and minimizing un [...]

What Makes MrBeast So Successful? 🔗

A deep dive into the strategies, mindset, and team culture that have made MrBeast one of the most successful creators on YouTube [...]

What's New in Express.js v5.0 🔗

A detailed look at the key changes and improvements in Express v5.0 and how to migrate your app [...]

Evolve or Become Irrelevant 🔗

Why staying relevant in tech means constantly adapting to new technologies and trends [...]

Speculation Rules API: Boosting Web Performance with Prefetching and Prerendering 🔗

How the Speculation Rules API improves web performance by prefetching and prerendering future navigations [...]

Company Culture Happens Outside Management 🔗

Why real company culture grows from the ground up, not top down. [...]

Improve PageSpeed Insights Score with Lazy Loading Iframes 🔗

How to save bandwidth and speed up your site by lazy-loading iframes [...]

Speed Up Your Website With rel='preconnect' and increase PageSpeed Insights Score 🔗

Using link rel='preconnect' can improve your website's performance by reducing connection setup times to key external domains. [...]

The Crutch Effect: How AI Tools Became A Crutch 🔗

Introducing The Crutch Effect [...]

Mental Toughness is the Best Quality a Developer Can Have 🔗

Mental toughness gets developers through challenges like debugging, picking up new tools, and hitting tight deadlines. It’s about staying calm and pus [...]

When Should You Actually Worry About Tech Debt? 🔗

Technical debt isn't the monster under your bed, but it can become one if ignored too long. [...]

Google is Killing Information Economics on the Internet 🔗

Google’s Gemini pulls summaries from websites and slaps them directly into the search results [...]

Tips for Reducing Cyclomatic Complexity 🔗

Cyclomatic complexity is like counting how many ways a car can go. More options make it harder to drive because you have to make more decisions, which [...]

setImmediate() vs setTimeout(0) in Node.js: What's the Difference? 🔗

setImmediate runs after I/O, setTimeout(0) runs after the timer phase. Here's when to use each, with event loop diagrams. [...]

Unrealistic Deadlines In Software Engineering 🔗

Unrealistic deadlines are more than just stressful—they set engineers up for failure [...]

Understanding JavaScript Closures With Examples 🔗

Closures are essential for creating functions that maintain state, without relying on global variables. [...]

Explicit is better than implicit 🔗

Clarity is key: being explicit makes your code more readable and maintainable. [...]

AggregateError in JavaScript 🔗

Handle multiple errors at once [...]

Comprehensive React Testing: Handling API Calls with Mock Service Worker 🔗

Testing can be tricky, especially when it comes to handling API calls. [...]

Chrome Is Beta Testing Built-In AI. Could This Kill a Lot of Startups? 🔗

The Power Play: Gemini Nano in Chrome [...]

Embrace Intermediate Variables and Early Returns in JavaScript 🔗

Early returns and intermediate variables make your code easier to reason about [...]

When Regex Goes Wrong 🔗

Issues and catastrophic failures caused by regex [...]

Invisible columns in SQL 🔗

It’s a small feature, but it can make a big difference. [...]

Understanding Vue's Suspense 🔗

How the Suspense component manages async dependencies and improves loading states in Vue apps [...]

The Only Widely Recognized JavaScript Feature Ever Deprecated 🔗

The 'with' statement is the only feature ever deprecated in JavaScript [...]

10 Essential Terminal Commands Every Developer Should Know 🔗

List of useful Unix terminal commands to boost your productivity. Here are some of my favorites. [...]

Remove Unnecessary NPM Packages with eslint-plugin-depend 🔗

We don't need packages to handle basic JavaScript tasks [...]

Common Causes of Memory Leaks in JavaScript 🔗

Identify and fix common JavaScript memory leaks (Node.js and Deno.js) [...]

Secure Your Repositories: Prevent Credential Leaks with Gitleaks 🔗

Automate security flows and ensure your team follows security best practices [...]

Technical Debt Is Killing Your Business 🔗

And it will be your downfall if you choose to ignore it [...]

Frontend Security Checklist 🔗

Tips for Keeping All Frontend Applications Secure [...]

Demystifying React Hooks 🔗

Hooks can save you time and improve the quality of your code [...]

The Secret to Being a Top Developer Is Building Things 🔗

You can only become a great developer if you're willing to put effort into it [...]