The Ultimate Guide to HTTP/2: What Makes It Better?

Ever since the development of the HyperText Transfer Protocol (HTTP), the World Wide Web has used it to deliver content. The Web has adopted several HTTP versions, and each update...

Anissa Maligat
Anissa Maligat June 29, 2021

Ever since the development of the HyperText Transfer Protocol (HTTP), the World Wide Web has used it to deliver content. The Web has adopted several HTTP versions, and each update includes essential enhancements for optimal data transfer and simple, flexible use.

HTTP started out as the one-line HTTP/0.9 protocol, a process that only fetched HTML files. It then evolved into HTTP/1.0, the first protocol to use headers for sending other documents. Later on, that version was replaced by HTTP/1.1. Modern web browsers currently use HTTP/1.1 as their standard HTTP protocol.

Since its inception, HTTP/1.1 has provided developers with several remarkable features. However, that version struggled with speed, security, and user-friendliness. That’s where the new HTTP/2 protocol comes in.

But you might wonder, “What is HTTP/2.0 and how will it help my website perform better?” To answer this question, we’re giving you a closer look at all things related to HTTP/2. Read on to learn more about HTTP’s newest version.

What is HTTP/2?

2015 saw a big overhaul of HTTP/1.1 with the introduction of HTTP/2. With Google’s SPDY (speedy) protocol as its basis, the newest HTTP protocol focused on delivering quick page loading times and reduced round-trip time (or the time it takes for browsers to send and get requests). HTTP/2 aims to reach those goals for a better experience on web pages, including resource-heavy ones.

But what exactly is the SPDY protocol? It’s a process that improved how HTTP handles requests and responses. SPDY came with features such as Transmission Control Protocol (TCP) pipelining and mandatory compression for less latency while browsing. 

At first, HTTP/2 was derived from SPDY. But it eventually set itself apart from Google’s protocol and introduced features like a fixed header compression algorithm. We’ll get to these features in the next section.

HTTP/1.1 vs. HTTP/2.0: What’s the Difference?

HTTP/2.0 came with several enhancements to help ensure that users get content faster and have a better browsing experience. Let’s look at each of these changes and how they’re different from HTTP/1.1’s features.

Binary Framing Layer

HTTP/1.1 usually transmits plain text requests and responses, while HTTP/2 converts messages into binary with a binary frame layer. Thanks to the feature, HTTP/2.0 can send binary data with the same verbs, methods, headers, and other semantics. The protocol can use new data delivery processes as well, making it different from HTTP/1.1.

Delivery Models

Speaking of data delivery, HTTP/1.1 and HTTP/2 leverage unique delivery models. Here’s how each framework works.

HTTP/1.1: Pipelining & Head-of-Line Blocking

After a client sends an HTTP GET request, the protocol usually delivers a page with links to necessary resources for the requested page. That page will only load if it has those resources, and the client will have to retrieve them with multiple requests.

HTTP/1 had clients sending new requests after reconnecting to the TCP protocol. But when HTTP/1.1 rolled out, it resolved the issue through persistent connections and pipelining. Persistent connections work through an always-open TCP connection that lets clients make multiple requests over that connection consistently.

But sometimes, head-of-line blocking (HOL) can take place. HOL occurs when the first request in a queue blocks other requests, particularly after receiving none of its necessary resources.

HTTP/2: Multiplexing

Unlike HTTP/1.1 which used pipelining, HTTP/2 features multiplexing. Multiplexing lets the protocol transmit multiple requests simultaneously via TCP, allowing servers and browsers to serve multi-resource web pages. In doing so, HTTP/2 resolves head-of-line blocking.

Control Over Buffer Space

Clients and servers on TCP connections use a set amount of buffer space for incoming requests. By leveraging buffers, those systems can handle intermittent connections and multiple or substantial requests.

However, clients and servers can also have limited space to accommodate HTTP requests. Small buffer sizes can lead to overflow, and HTTP/1.1 and HTTP/2 tackle this problem in different ways.

HTTP/1.1: TCP Connections

In HTTP/1.1, a TCP connection handles buffer overflow. Clients and servers would connect to the protocol and base buffer sizes on their default settings. In some cases, the receiver would relay its remaining buffer space or receive a window to the sender. This scenario applies if the receiver has some data in its buffer.

When the receiver sends its receive window, that message will be delivered in an ACK packet. Through the packet, the sender would know that the receiver picked up the opening signal. But there are times where the sender won’t transmit any data. That’s because the receiver would have zero buffer space.

It’s also notable that HTTP/1.1 prevents buffer overflow with its transport layer. As a result, new TCP connections would need their own flow control process. But with its multiplexing capabilities, HTTP/2 takes a different approach to a buffer overflow.

HTTP/2: Client & Server Control

As HTTP/2.0 implements multiplexing, receive windows over TCP connections won’t be able to control single stream transfers. Having clients and servers handle the flow of data streams helps the protocol avoid the issue.

Instead of using their default settings to determine buffer sizes, clients and servers can base their receive windows on the amount of multiplexed streams. These systems do so when they get the available buffer space from the application layer. More than that, a WINDOW_UPDATE frame can help adjust or maintain HTTP/2’s flow control capabilities.

Processes for Resource Requests

Whenever a client requests a web page, they will typically get an index page. Loading that page might require more resources, leading to more requests from the client. In turn, those requests could translate to more loading time. Let’s look at how HTTP/1.1 and HTTP/2 deal with this problem.

HTTP/1.1: Resource Inlining

Resource inlining involves adding required resources to HTML documents that are transmitted to clients. Developers can use this method if they’re already aware of any necessary resources for specific web pages.

Unfortunately, resource inlining has developed the following issues:

That said, resource inlining keeps clients from setting resources and documents apart.

HTTP/2: Server Push

The server push method provides HTTP/2.0 servers with exceptional control for optimal connections. During this process, a server will place resources that a web page might need into a browser’s cache. This step can be done before the client asks for any necessary resources. As a result, browsers can show content to users right away.

Header Compression

HTTP/1.1 developers often go for smaller CSS and JavaScript files by compressing data in gzip and similar programs. However, servers tend to transmit plain text headers. These systems send slightly small headers, but that data can overwhelm the connection. As a result, API and resource-heavy web apps are affected.

Cookies can also pose a challenge when it comes to compression. While servers can deliver small headers, cookies can create larger ones. HTTP/2 fixes this issue with HPACK compression, a method that helps reduce header size.

HPACK works by creating smaller headers after those elements are split. It compresses headers with Huffman coding, which helps the program encode metadata for smaller headers. Lastly, HPACK can track and compress transmitted metadata fields.


In terms of security, HTTP/2 is still the best. Today’s web browsers use this protocol when users are on encrypted connections. In turn, it ensures higher user and application security.

What Makes HTTP/2 Effective?

Along with advanced features, HTTP/2.0 has several advantages over its predecessors. Here’s what makes this protocol great for your website.

Optimizes Mobile Web Performance

The last few years have seen more mobile web users. HTTP/2 understands current web usage trends — for instance, its features help achieve less latency while browsing on mobile. Additionally, this HTTP version offers high performance and security for a better mobile web experience.

Offers a Better Mobile Experience

To attract mobile users, online businesses are going “mobile-first.” The mobile-first strategy is all about providing those users with an optimal mobile experience. Sadly, not all types of mobile device hardware can keep up because of long processing times. Using HTTP/2 can result in faster load times and mobile network latency for a better mobile experience.

Helps Sites Deliver Media-Rich Content

Nowadays, the World Wide Web’s focus is on the quick delivery of media-rich content. Users want to consume their preferred content and services right away. However, some startups can’t afford a cloud-based platform to serve content right away. With features that can shrink resource sizes by several bytes, HTTP/2 can help you deliver media-rich content to users seamlessly.

Improves the Use of Various Technologies

Client and server requests are using more and more resources to serve media-rich content and render complex web designs. HTTP/2 is a viable and reliable answer to existing web optimization strategies, with features like header compression and multiplexing working toward better network usage.

Offers an Innovative Web Solution

Innovation and exceptional Web performance are two of HTTP/2’s best qualities. The SPDY protocol became the foundation of HTTP/2.0’s features, and those capabilities are on their way to supersede SPDY and older HTTP versions. By providing simpler approaches to optimizing web performance, HTTP/2.0 is practical for high-performing websites and online services.

Helps Enhance Website SEO

HTTP/2 can help your website rank higher on search engines as well. Overlooking the protocol and what it can do for your online business is a no-no, especially if your brand doesn’t have enough organic users. With HTTP/2.0, your business can compete with big brands and climb up the search ladder.

Build High-Performance Websites with HTTP/2

HTTP/2.0 is a far cry from previous HTTP protocols, with innovative features centered around optimal Web performance. Implementing this robust protocol can help your brand improve page loading speed, content delivery capabilities, and SEO performance. In turn, visitors can enjoy better UX.

Does your website need an overhaul? Growth Rocket’s web development experts are here to help you boost your storefront’s performance. Contact us today to get started.

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