Learn about web development, and more by Karthik Kadambi, full stack web developer
Grocery shopping in the US can be done entirely from your phone. Key Apps Instacart: Delivery from almost any store (Safeway, Costco, Sprouts). Walmart: Great for budget-friendly household items and groceries. Weee!: The best for Asian and Indian groceries (very popular among the immigrant community). Safeway/Kroger: Download the specific store app for digital coupons and rewards. Too Good To Go:…
If you live in the SF Bay Area, the Clipper card is your ticket to everything. One Card, All Agencies Whether you are taking the BART , MUNI buses/trains, Caltrain , or VTA , you only need one Clipper card. How to Use Digital Card: You can add a Clipper card directly to your Apple Wallet or Google Pay. You don't even need a physical card anymore! Autoload: Set up "Autoload" so your card never runs…
Costco is a US institution. It's a warehouse-style store where items are sold in bulk. Membership Levels Gold Star ($65/year): The basic membership. Executive ($130/year): Gives you 2% cashback on most purchases. If you spend more than $3,250 a year, it pays for itself. The Draw Gas: Their gas is almost always the cheapest in town. Rotisserie Chicken: A $4.99 staple. Kirkland Signature: Their…
As an H1B holder, you'll inevitably need to send money back home (e.g., to India) for family, savings, or investments. While traditional bank wires are an option, digital platforms usually offer much better exchange rates and lower fees. Choosing the Right Service The "best" service often depends on whether you prioritize speed, exchange rates, or convenience. For Speed: Remitly (Express) and Xoom…
The US healthcare system is notoriously complex. Here's a quick primer on the terms you'll see during your company's "Open Enrollment." Key Terms Premium: What you pay every month (usually deducted from your paycheck). Deductible: What you pay out-of-pocket before insurance kicks in. Copay: A flat fee you pay for a doctor's visit (e.g., $20). Out-of-Pocket Max: The most you'll ever have to pay in…
A Health Savings Account (HSA) is one of the best financial tools available in the US if you have a High Deductible Health Plan (HDHP). The Triple Tax Advantage Tax-free contributions: Money goes in before taxes (lowering your taxable income). Tax-free growth: Any investments made within the HSA grow without being taxed. Tax-free withdrawals: As long as you use the money for qualified medical…
The 401(k) is the standard employer-sponsored retirement plan in the US. The "Free Money" Match Most companies offer a "match" (e.g., if you contribute 6%, they also give you 6%). This is literally free money and is the first thing you should maximize. Traditional vs. Roth Traditional 401(k): Contributions are made pre-tax (lowers today's taxes). You pay taxes when you withdraw in retirement. Roth…
One of the best values in the US is the Public Library . It's not just about books! How to Join Just walk into your local library with a proof of residency (like a utility bill or lease) and your ID. Membership is free. The Perks Digital Content: Use the Libby app for free ebooks and audiobooks. Movies: Use Kanopy or Hoopla for free streaming of documentaries and films. Museum Passes: Many…
When you first move, you likely need a lot of furniture. OfferUp (and Facebook Marketplace) are the best places to find high-quality used items at a fraction of the retail price. Tips for Success Safety First: Always meet in a public place. Many police departments have "Safe Exchange Zones" for this purpose. Negotiate: Don't be afraid to offer a slightly lower price, but be respectful. Check…
Today marks exactly four years since I landed in the United States. It’s been a journey filled with growth, challenges, and a lot of paperwork. Looking back, the first few months were a blur of "firsts"—my first SSN, my first bank account, my first apartment. Transitioning to life in the US, especially on an H1B visa, involves navigating a complex web of systems. To commemorate this milestone,…
Rent is usually the largest expense for any new immigrant. While most landlords charge a 3% fee for credit card payments, Bilt 2.0 solves this while letting you earn valuable travel points and cash back. How Bilt 2.0 Works With the 2.0 update, Bilt has shifted how it handles payments to be even more seamless: ACH Direct Pull: Bilt pulls funds directly from your linked bank account via ACH. This…
Once you've had your BoFA checking account for a few months and your credit score (started by Zolve) is appearing, you can apply for a Bank of America Credit Card . The Opportunity No SSN (Initially): If you still don't have your SSN card but have your bank account, BoFA is often willing to issue a card based on your internal banking history with them. Customized Cash Rewards: Their most popular…
The internet isn't a single thing, it's a series of handshakes, lookups, and translations that happen in milliseconds. Let's trace a single request from your keyboard to a database halfway across the world. Most of us take it for granted: you type a URL, hit enter, and a fraction of a second later, a world of information appears. But between that keystroke and the rendered page lies a complex,…
In today's world, internet is as vital as water and electricity. In the US, the provider you choose often depends on your specific apartment builder's wiring. Main Providers Xfinity (Comcast): Very common, easy self-install kits. AT&T Fiber: Extremely fast if available in your area. Sonic: Great local provider in parts of the Bay Area. Self-Install vs. Technician Most providers offer a…
In most of the US, a Driver's License (DL) is essential for daily life. Even if you have an international license, it's usually only valid for a few months after you establish residency. The Process Written Test: Take a knowledge test at the DMV. You can study using the handbook available on the DMV website. Behind-the-Wheel Test: Once you pass the written test, you'll get a permit to practice.…
The Social Security Administration (SSA) is not just where you get your card; it's a lifelong agency you'll interact with. Your SSA Account Once you have your SSN, you should create an account online. This allows you to: Verify your yearly earnings (important for future retirement benefits). Update your contact info. Get estimates for retirement or disability benefits. Crucial Note: Errors in your…
USCIS (United States Citizenship and Immigration Services) is the agency that handles your legal status in the US. Key Tasks i-94 Travel History: Whenever you enter or leave the US, check your i-94 to ensure the "Admit Until" date is correct. This is your official record of admission. Change of Address (AR-11): You are legally required to notify USCIS within 10 days of moving to a new address.…
If you don't plan on driving immediately, a State ID is a great way to have a US-issued photo ID without carrying your passport everywhere. What is a REAL ID? Starting May 7, 2025 (check current dates), you'll need a "Real ID" compliant license or ID to board domestic flights or enter certain federal buildings. It's marked with a gold star. How to Get One Location: Visit your local DMV (Department…
The Social Security Number (SSN) is your primary identifier for almost everything in the US—from getting paid to opening bank accounts and renting. The Timeline You usually need to wait about 10 days after landing in the US before applying, to ensure your arrival status has been updated in the SAVE system. How to Apply Start Online: It is much faster to start your application online at the…
If you are living in Northern or Central California, PG&E (Pacific Gas and Electric) will likely be your utility provider. How to Setup Online: Visit the PG&E website and select "Start Service." Details: You'll need your new address and the date you want the service to begin (usually your move-in date). Identification: You might be asked for an SSN. If you don't have one yet, you may need to call…
Bank of America (BoFA) is often the preferred choice for new H1B arrivals because they are generally more accommodating to those without an SSN yet. Requirements To open an account, you usually need: Passport: Your primary identification. i797B (Approval Notice): Proof of your legal status and authorization to work. US Address: To receive your debit card and statements. The Process Walk into a…
Finding a place to live is one of the most stressful parts of moving. Without credit history, it can be challenging, but not impossible. The Search Apps: Zillow, Apartments.com, and Redfin are your best friends. Leasing Offices: In the US, most large apartment complexes have on-site leasing offices. You can walk in for a tour. Requirements for Newcomers Since you won't have a credit score yet,…
Communication is the first thing you need after landing. Getting a local SIM card is essential for everything from calling a cab to filling out forms that require a US phone number. Popular Options T-Mobile: Often has great plans for newcomers and good international roaming features. AT&T: Reliable coverage across most states. Mint Mobile: A great budget-friendly option that uses T-Mobile's…
When moving to the US, one of the biggest "chicken and egg" problems is credit history. You need credit history to get a credit card, but you need a credit card to build history. Zolve is a great solution for this. They allow you to apply for a US credit card and bank account while you are still in your home country (like India) using your visa and passport. Why Zolve? No SSN required initially:…
The Border Gateway Protocol (BGP) is the postal service of the Internet. When someone drops a letter into a mailbox, the Postal Service looks at the address and chooses a fast, efficient route to deliver that letter. BGP does the same for the Internet. The Internet is a network of networks. It’s made up of hundreds of thousands of individual networks known as Autonomous Systems (AS) . BGP is the…
The primary driver for IPv6 was the exhaustion of IPv4 addresses. IPv4 uses 32-bit addresses, allowing for about 4.3 billion unique addresses. In the early days of the Internet, this seemed like plenty. However, with the explosion of mobile devices, IoT, and always-on servers, we ran out. IPv6 uses 128-bit addresses , which allows for approximately 340 undecillion ($3.4 times 10^{38}$) addresses.…
WebSockets is a communication protocol that provides full-duplex communication channels over a single TCP connection. Unlike HTTP, which is strictly "request-response," WebSockets allow both the client and the server to send data at any time without waiting for the other party to ask for it. How WebSockets Work The Handshake: A WebSocket connection starts as a standard HTTP request. The client…
Caching is the process of storing copies of data in a temporary storage location (a cache) so that future requests for that data can be served faster. In the context of the web, caching happens at many different layers between the user and the server. Layers of Caching Browser Caching: Your web browser (Chrome, Firefox, Safari) stores images, scripts, and stylesheets on your local hard drive. When…
A proxy server acts as a gateway between you and the internet. It’s an intermediate server separating end users from the websites they browse. When you use a proxy server, internet traffic flows through the proxy server on its way to the address you requested. The request then comes back through that same proxy server, and then the proxy server forwards the data received from the website to you.…
Load balancing is the process of distributing incoming network traffic across a group of backend servers, also known as a server farm or server pool . Imagine a popular website that gets millions of visits a day. A single server wouldn't be able to handle all that traffic. A load balancer sits in front of the servers and acts as a "traffic cop," routing client requests to all servers capable of…
A Virtual Private Network (VPN) extends a private network across a public network and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network. In simpler terms, it creates a secure, encrypted "tunnel" through which your data travels, making your online activities much harder to track or intercept. How a…
A Content Delivery Network (CDN) is a geographically distributed group of servers that work together to provide fast delivery of Internet content. Most of the web's traffic is served through CDNs, including traffic from major sites like Facebook, Netflix, and Amazon. How a CDN Works The main goal of a CDN is to reduce latency —the delay between submitting a request for a web page and the page…
A firewall is a security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. It acts as a barrier between a trusted network (like an internal office network) and an untrusted network (like the Internet). How Firewalls Work Firewalls can be implemented in either hardware or software (or both). They inspect "packets" of data to see if they…
The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on IP networks. A DHCP server dynamically assigns an IP address and other network configuration parameters to each device on a network so they can communicate with other IP networks. The DORA Process When a device (client) joins a network, it goes through a four-step process to get an IP address, often remembered…
Network Address Translation (NAT) is a method used to remap one IP address space into another. In a typical home or office network, NAT allows multiple devices (laptops, phones, consoles) with "private" IP addresses to share a single "public" IP address provided by an ISP. Why NAT Exists The main reason for NAT is IPv4 address exhaustion . There are only about 4 billion IPv4 addresses. Without…
Inside homes, offices and data centers, most communication does not go directly to the internet. It happens within local networks. Network switches are the devices that make this internal communication fast and efficient. Switching is about moving data between devices on the same network. It works at a lower level than routing and focuses on MAC addresses rather than IP addresses. This article…
IP addresses tell us where a device is on a network. MAC addresses tell us who the device is locally. But there is a problem. When your computer wants to send data to another device on the same network, it knows the destination IP address but it does not know the destination MAC address. Ethernet and Wi-Fi require MAC addresses to deliver frames. ARP exists to solve this exact problem. This…
An IP address identifies a device on a network logically. But before IP can work, devices need a way to identify each other physically on the local network. That role is handled by MAC addresses. Every network device has a MAC address. It operates at a lower level than IP and plays a critical role in how data moves inside local networks like your home Wi-Fi or office LAN. This article explains…
Ports and Protocol Numbers Explained. How One IP Address Serves Many Applications Introduction An IP address identifies a device on a network. But one device can run many applications at the same time. You might be browsing the web, listening to music, syncing files, running a local server and chatting on messaging apps. If all those applications shared the same IP without a way to distinguish…
Most people learn TCP first because it handles reliable delivery. But the internet needs a second transport protocol that focuses on speed. That protocol is UDP. It is simple. It is fast. It is used everywhere communication must be real time. Many modern applications rely on UDP to deliver data quickly even if some packets get lost. This article explains what UDP is, why it exists and where it is…
TCP and IP are the two most critical protocols that define how data moves across the internet. Together they form the TCP IP model that almost every network uses. One handles addressing. The other handles reliable delivery. This article explains their roles and how they work together to move data across billions of devices. What IP does IP stands for Internet Protocol. It handles addressing and…
As 2025 comes to a close, I find myself sitting with a profound sense of gratitude. It’s been a year of immense learning, some hard truths, and ultimately, a clearer vision for what comes next. Gratitude and Reflection First and foremost, I am incredibly grateful for this year. Despite its ups and downs, 2025 has been a teacher. It taught me resilience, it showed me the value of patience, and it…
HTTP/3 is the newest version of the HTTP protocol. It solves long standing performance issues by moving from TCP to QUIC. This makes web browsing faster especially on mobile and unstable networks. This article explains what HTTP/3 changes and why it matters. Why HTTP/3 was created HTTP/1.1 and HTTP/2 both use TCP. TCP is reliable but slow to recover from packet loss. TCP also suffers from head of…
HTTPS is simply HTTP running inside a secure TLS connection. It provides safety, privacy and integrity. Every major website uses HTTPS because it protects users and builds trust. This article explains how HTTPS works, how it connects with TLS and why it is the default for every modern website. What is HTTPS HTTPS stands for Hypertext Transfer Protocol Secure. It adds encryption and authentication…
When you enter a password or make an online payment you are trusting the website to keep your information safe. SSL and TLS are the technologies that protect your data while it travels across networks. Without them anyone on the path between you and the website could intercept or modify your information. This article explains what SSL and TLS are, how they work and why they matter. What SSL and…
Every time you open a web page your browser talks to a web server using a protocol called HTTP. This communication defines how requests are sent and how responses are received. It is the language of the web. Understanding HTTP helps you understand how the internet delivers content, runs applications and loads websites. What is HTTP HTTP stands for Hypertext Transfer Protocol. It is a set of rules…
Everything that travels across the internet moves in small pieces called packets. A packet is the most fundamental part of digital communication. Even large files like movies or software downloads do not travel as a single unit. Instead, they are divided into thousands or millions of packets. This design makes the internet fast. It also makes it fault tolerant and scalable. This article breaks…
Every website begins with a domain name. Before DNS can map a domain to an IP address, the domain must be registered. This article explains how domain names are created, bought, owned, and managed. What is a Domain Name A domain name is a unique, human-readable label used to identify websites. Examples: google.com karthikkadambi.com A domain name points to the servers that host your website. Who…
A website needs a place to store files, images, code, and databases. Hosting is the service that stores these files on a server and delivers them to visitors through the internet. Core Idea You rent space on a server. When users type your domain, the server sends your website to their browser. Main Hosting Types 1. Shared Hosting: Many websites share one server. Cheap and basic. 2. VPS Hosting:…
Every website on the Internet is hosted on a server that has an IP address. Humans are not good at remembering long numbers. So the internet uses DNS, also called the Domain Name System. DNS converts human-readable names into machine-friendly IP addresses. When you type google.com or youtube.com , DNS finds the correct IP address and sends it back to your device. Without DNS, the internet would…