Service

/ˌtiː-siː-ˈpiː/

n. “Reliable conversations over an unreliable world.”

TCP, short for Transmission Control Protocol, is one of the core protocols of the Internet protocol suite. It provides reliable, ordered, and error-checked delivery of data between applications running on hosts connected to a network. TCP works hand-in-hand with IP, forming the ubiquitous TCP/IP foundation of modern networking.

Unlike protocols that send packets blindly, TCP establishes a connection between sender and receiver through a handshake process, ensures that packets arrive in order, retransmits lost packets, and manages flow control to prevent congestion. This reliability makes it ideal for applications where correctness is crucial, such as web browsing (HTTP), email (SMTP), file transfers (FTP), and secure connections (TLS/SSL).

A typical TCP session begins with a three-way handshake: SYN, SYN-ACK, and ACK. This establishes the connection, allowing both ends to track sequence numbers and manage data segments. Once the connection is open, data can flow reliably until one side closes the connection with a FIN or RST signal.

TCP also supports multiplexing via port numbers, enabling multiple simultaneous conversations between hosts. For instance, your browser might use port 443 for HTTPS while an email client simultaneously uses port 993 for IMAP, all running over TCP without interference.

While reliable, TCP is heavier than connectionless protocols like UDP, introducing additional overhead and latency due to acknowledgments, retransmissions, and flow control. Nevertheless, this reliability is often essential: imagine a web page missing half its HTML or a financial transaction packet dropped mid-transfer. TCP ensures that does not happen.

In practice, TCP is everywhere. Your browser, email client, instant messaging apps, and even secure VPNs like OpenVPN or WireGuard rely on TCP (or optionally UDP) for reliable communication. Tools like curl and fetch operate over TCP by default, trusting it to deliver the request and response accurately.

In summary, TCP is the workhorse of the internet. It guarantees that what you send is what your peer receives, in the right order and without corruption. Every time you load a website, send an email, or securely transfer a file, TCP is quietly orchestrating the exchange, proving that reliability at scale is not just a dream, it’s a protocol.

/ˌɛs-ɛf-ti-ˈpi/

n. “Securely moving files without looking over your shoulder.”

SFTP, short for SSH File Transfer Protocol or sometimes Secure File Transfer Protocol, is a network protocol that provides secure file transfer capabilities over the SSH (Secure Shell) protocol. Unlike traditional FTP, which sends data in plaintext, SFTP encrypts both commands and data, ensuring confidentiality, integrity, and authentication in transit.

Conceptually, SFTP looks like FTP: you can list directories, upload, download, delete files, and manage file permissions. But under the hood, all traffic is wrapped in an encrypted SSH session. This eliminates the need for separate encryption layers like FTPS while preventing eavesdropping and man-in-the-middle attacks.

A typical SFTP workflow involves connecting to a remote server with a username/password or SSH key, issuing commands like get, put, or ls, and transferring files through the secure channel. Clients like FileZilla, WinSCP, and command-line sftp utilities are commonly used to interact with SFTP servers.

SFTP is widely used for secure website deployment, backing up sensitive data, or exchanging large files between organizations. For example, a development team may deploy new web assets to a production server using SFTP, ensuring that credentials and content cannot be intercepted during transfer.

The protocol also supports advanced features like file permission management, resuming interrupted transfers, and atomic file operations. Because it operates over SSH, SFTP inherits strong cryptographic algorithms, including AES and HMAC, for encryption and authentication.

While SFTP is similar in appearance to FTP, it is a completely different protocol and is often preferred whenever security and compliance are concerns, such as for GDPR or CCPA regulated data transfers.

SFTP is not just FTP over SSH; it’s a purpose-built, secure protocol that keeps files safe in transit while offering the same flexibility that made FTP useful for decades.

/ˌɛf-ti-ˈpi/

n. “Moving files, one connection at a time.”

FTP, short for File Transfer Protocol, is one of the oldest network protocols designed to transfer files between a client and a server over a TCP/IP network. Dating back to the 1970s, it established a standardized way for computers to send, receive, and manage files remotely, long before cloud storage and modern APIs existed.

Using FTP, users can upload files to a server, download files from it, and even manage directories. Traditional FTP requires authentication with a username and password, although anonymous access is sometimes allowed. Secure variants like SFTP and FTPS encrypt data in transit, addressing the original protocol’s lack of confidentiality.

A basic FTP session involves connecting to a server on port 21, issuing commands like LIST, RETR, and STOR, and transferring data over a separate data connection. While this architecture works, it can be blocked by firewalls or NAT devices, leading to the development of passive FTP and more secure alternatives.

Despite its age, FTP remains in use for legacy systems, website deployments, and certain enterprise workflows. Modern developers may prefer HTTP or SFTP for file transfers, but understanding FTP provides historical context for networked file sharing, permissions, and protocol design.

Example usage: uploading website assets to a hosting server, downloading datasets from a remote repository, or syncing files between office systems. FTP clients like FileZilla, Cyberduck, and command-line tools remain widely deployed, proving the protocol’s resilience and longevity.

FTP does not inherently encrypt credentials or files. When security matters, combine it with secure tunnels like SSH or use its secure alternatives. Its legacy, however, lives on as a foundational protocol that influenced modern file-sharing standards.

/ˌɛks-ɛm-ɛl-ˌhɪt-ti-pi rɪˈkwɛst/

n. “Old school, but still gets the job done.”

XMLHttpRequest, often abbreviated as XHR, is a JavaScript API that enables web browsers to send HTTP requests to servers and receive responses without needing to reload the entire page. Introduced in the early 2000s, it became the backbone of what we now call AJAX (Asynchronous JavaScript and XML), allowing dynamic updates and interactive web applications.

Despite the name, XMLHttpRequest is not limited to XML. It can handle JSON, plain text, HTML, or any type of response. A typical request looks like:

const xhr = new XMLHttpRequest();
xhr.open('GET', '/api/data', true);
xhr.onload = function() {
  if (xhr.status === 200) {
    console.log(JSON.parse(xhr.responseText));
  }
};
xhr.send(); 

Here, open sets up the HTTP method and URL, onload handles the response, and send dispatches the request. Errors and progress events can also be monitored using onerror and onprogress handlers, providing fine-grained control over network communication.

XMLHttpRequest has largely been superseded by the fetch API in modern development, which offers a cleaner, promise-based approach and improved readability. However, XHR remains relevant for legacy applications, older browsers, and cases where fine-grained event handling or synchronous requests are needed.

In practical terms, XMLHttpRequest enabled a shift from static, page-reloading websites to dynamic web apps, laying the foundation for single-page applications (SPAs) and real-time data updates that we take for granted today. Its design influenced modern APIs like fetch, and understanding XHR is essential for maintaining or interfacing with older web systems.

/fɛtʃ/

v. “Go get it — straight from the source.”

fetch is a modern JavaScript API for making network requests, replacing older mechanisms like XMLHttpRequest. It provides a clean, promise-based interface to request resources such as HTML, JSON, or binary data from servers, making asynchronous operations much more readable and manageable.

At its simplest, fetch('https://api.example.com/data') sends a GET request to the specified URL and returns a Promise that resolves to a Response object. This response can then be converted into JSON via response.json() or plain text via response.text(). For example:

fetch('https://api.example.com/users')
  .then(response => response.json())
  .then(data => console.log(data)); 

fetch supports all standard HTTP methods: GET, POST, PUT, PATCH, DELETE, etc., and allows customization through headers, body content, credentials, and mode (such as cors or no-cors). This flexibility makes it ideal for interacting with REST APIs or modern web services.

Unlike curl or older XMLHttpRequest approaches, fetch leverages JavaScript Promises, which allows for straightforward chaining, error handling, and asynchronous logic without the callback hell that plagued older methods. Errors like network failures or server rejections can be caught cleanly with .catch().

fetch also supports streaming responses, enabling partial processing of data as it arrives, which is useful for large files, live feeds, or progressive data consumption. Combined with JSON parsing and modern ES6 features, it provides a robust, readable way to interact with the network directly from the browser or JavaScript runtime environments like Node.js.

In practice, using fetch can simplify web application development, improve maintainability of API calls, and allow developers to handle network operations in a predictable, elegant way. It has become the default method for network requests in modern front-end development, and understanding it is crucial for any developer working with the web today.

/kərl/

n. “Talk to the internet without a browser.”

cURL is a command-line tool and library (libcurl) for transferring data with URLs. It supports a vast array of protocols, including HTTP, HTTPS, FTP, SMTP, and more, making it a Swiss Army knife for internet communication and scripting.

At its core, cURL allows users to send requests to remote servers and retrieve responses. For example, curl https://example.com fetches the HTML of a web page, while curl -X POST -d "name=Chris" https://api.example.com/users can submit data to an API endpoint. This makes it invaluable for testing, automation, and interacting with REST APIs.

cURL is also scriptable and works in batch operations, allowing repeated requests or data fetching without manual intervention. It can handle authentication headers, cookies, and SSL certificates, bridging the gap between human-readable browsing and programmatic interactions.

Developers often pair cURL with JSON or XML responses to automate tasks, test endpoints, or debug network interactions. For example, extracting user data from an API or sending log files to a remote server can be accomplished seamlessly.

While simple in its basic form, cURL is powerful enough to act as a full-fledged HTTP client. It is available on most operating systems, embedded in scripts, CI/CD pipelines, and even used by SaaS platforms to test and integrate external services.

Understanding cURL equips anyone dealing with networking, web development, or automated workflows to interact with the internet directly, bypassing browsers and GUIs, providing precision and reproducibility for testing, troubleshooting, and data transfer.

/krʊd/

n. “Create, Read, Update, Delete — the alphabet of persistent data.”

CRUD is an acronym representing the four fundamental operations that can be performed on persistent storage or resources in a database or application: Create, Read, Update, and Delete. These operations form the backbone of most software systems, allowing users and applications to manage data effectively.

In a REST context, CRUD operations map naturally to HTTP methods: POST for Create, GET for Read, PUT or PATCH for Update, and DELETE for Delete. This alignment simplifies API design and ensures that client-server interactions remain consistent and predictable.

For example, consider a CRUD interface for managing a contacts database. Create adds a new contact, Read retrieves contact details, Update modifies an existing contact’s information, and Delete removes a contact from the system. These four operations cover nearly all use cases for data management.

CRUD is not limited to relational databases; it applies to document stores, key-value stores, cloud services, and even local file systems. When combined with REST principles, CRUD provides a universal language for designing scalable and maintainable APIs.

Understanding CRUD is essential for developers, system architects, and anyone designing interactive applications. It provides a conceptual framework that ensures every data interaction has a clear purpose, promotes consistency, and reduces the likelihood of unintended side effects.

Many modern tools, frameworks, and platforms provide CRUD scaffolding or generators, allowing developers to quickly implement data management functionality while following best practices. Whether in web development, mobile apps, or enterprise systems, CRUD remains the fundamental model for interacting with data.

In short, CRUD is simple, pervasive, and indispensable: the unspoken grammar of data operations that powers everything from tiny scripts to massive cloud services.

/rɛst/

n. “Architect it once, call it anywhere.”

REST, short for Representational State Transfer, is an architectural style for designing networked applications. It emphasizes a stateless client-server communication model where resources are identified by URIs, and interactions are carried out using standard HTTP methods like GET, POST, PUT, PATCH, and DELETE.

In a RESTful system, each resource can be represented in multiple formats such as JSON, XML, or HTML. The server provides the representation, and the client manipulates it using HTTP verbs. REST is stateless: every request contains all information necessary for the server to process it, which improves scalability and simplifies reliability across distributed systems.

For example, a REST API might expose a resource at /users/123. A GET request retrieves the user, a PUT request updates the user, a PATCH request partially modifies the user, and a DELETE request removes the user.

REST is not a protocol or standard — it is a style of designing services. Constraints like uniform interfaces, stateless interactions, cacheable responses, layered system architecture, and code-on-demand (optional) guide developers to build simple, scalable, and flexible APIs. Adhering to these principles makes applications easier to maintain and allows clients written in different languages or platforms to interact seamlessly.

REST powers much of the modern web. Social media platforms, SaaS applications, cloud services like IaaS, PaaS, and microservices architectures often expose RESTful APIs. Its design encourages clear separation of concerns: the server manages resources, while the client handles presentation and state transitions.

Consider a developer building a dashboard that aggregates user data from multiple services. By leveraging REST APIs, they can fetch JSON representations from different servers, combine the data, and display a unified interface — all without needing specialized protocols or complex bindings.

While REST is widely used, alternatives like GraphQL or gRPC exist, offering different trade-offs in flexibility and efficiency. Nevertheless, REST remains a cornerstone of web architecture, emphasizing simplicity, statelessness, and universal compatibility through standardized HTTP mechanisms.

/ˈā-ˈēs-ˈpē/

n. “The gatekeeper of your connection.”

ISP, short for Internet Service Provider, is a company or organization that provides individuals and businesses access to the internet. From the early days of dial-up to modern fiber-optic and 5G connections, ISPs serve as the critical link between your device and the vast expanse of the web.

At its core, an ISP handles routing, addressing, and delivering data packets between your device and the servers hosting websites, applications, and services. ISPs assign IP addresses, manage bandwidth allocation, and often provide additional services like email hosting, DNS resolution, and web hosting.

Practically speaking, without an ISP, your computer, smartphone, or IoT device cannot reach online resources. They also play a significant role in shaping user experience: faster, more reliable ISPs reduce latency for streaming video, gaming, or real-time collaboration, while slower or congested networks can cause interruptions.

While ISPs enable connectivity, they are also points of control and observation. Many maintain logs of user activity for legal compliance, billing, or network management. Privacy-conscious users often combine ISPs with tools like PIA, VPNs, or TLS encryption to obscure their activity from the ISP itself.

ISPs operate in many forms: consumer broadband, business-grade connections, mobile data networks, and even satellite or fixed wireless services. They also enforce policies, which can include traffic shaping, content filtering, or usage limits, depending on jurisdiction and service agreements.

For example, streaming a high-definition video from a content delivery network (CDN) requires coordination between your device, the CDN servers, and the ISP. A well-provisioned ISP ensures smooth delivery, while a mismanaged or overloaded ISP could cause buffering or downtime.

Understanding your ISP is crucial not only for technical troubleshooting but also for navigating privacy, security, and regulatory considerations online. Selecting an ISP often involves evaluating speed, reliability, pricing, and policies on logging, net neutrality, and data retention.

In essence, an ISP is both a facilitator and gatekeeper of your online life. It enables communication, commerce, and content delivery, but also represents a layer where privacy, control, and security intersect. Tools like PIA, TLS, and VPN help users navigate these realities safely and privately.