Performance Overview

This document provides brief summaries of the major features of Instart Web Performance, with links for more detail.

Instart's innovative performance optimization features provide a completely new way to accelerate web application delivery, especially for mobile devices connected via wireless networks.

  • HTML Streaming and JavaScript Streaming features take advantage of web application virtualization to send application elements in small chunks instead of as monolithic downloads, thereby improving performance by reducing idle processing time in the browser.
  • Dynamic Caching predictively preloads dynamically-generated web pages and serve them from cache to first-time visitors.
  • Image Transcoding with SmartVision optimizes image file size, format and compression to provide fast performance without sacrificing image quality.
  • Image Adaptation provides a query string-based API for resizing image dimensions, cropping, and other transformations.

HTML Streaming

With traditional web delivery approaches, personalized dynamic HTML must be generated for each request before any content can be sent back to the requesting browser. The browser makes a request, and then there is a delay while the back end web and application servers generate the user-specific HTML and deliver it over the global Internet to the requesting browser. Traditional content delivery services therefore provide only basic network acceleration for dynamic HTML.

To overcome this obstacle, Instart has invented a new technology called HTML Streaming. The technology is based on the recognition that most "dynamic" HTML is not completely dynamic – that is, there are often significant parts of it that do not change (for example, the CSS and JavaScript used on the page), and other parts that do (such as user-specific content). HTML Streaming distinguishes between the unique and non-unique dynamic HTML, and saves time by streaming the non-unique dynamic HTML from an Instart server close to the end user's browser while the backend server is generating the unique dynamic HTML.

The browser can then make use of previously wasted time, as it can begin processing the non-unique parts of the HTML while the backend server is generating the unique HTML. The browser can begin rendering the page, and soon after, using the client-side Nanovisor, seamlessly patch in the remaining HTML when it arrives. Without HTML Streaming, these logically separate activities could only occur sequentially. The result is a dramatic decrease in the time it takes to respond to dynamic requests – meaning that the browser can start rendering the page sooner.

For details, see the HTML Streaming section.

JavaScript Streaming

The JavaScript Streaming feature improves performance by breaking down monolithic JavaScript code into fragments and streaming those fragments to the browser in prioritized order. It doesn't re-write or alter any source code – it simply packages the most used functions together so that the browser can begin parsing/executing the code sooner. JavaScript Streaming takes advantage of Instart's machine learning technology to make intelligent packaging decisions by learning how the code is actually executed.

For details, see the JavaScript Streaming section.

Dynamic Caching

Instart's Dynamic Caching creates the optimal user experience for customers' new site visitors, eliminating the delay these visitors usually experience when loading a new website for the first time. This new feature enables Instart's service to predictively preload dynamically-generated web pages and serve them from cache to first-time visitors. By avoiding the round trip back to the customer's origin, Dynamic Caching improves performance by 30 to 50% for first-time visits to a customer's website.

Commonly, for a first-time visitor to a website, the HTML response is essentially the same across all users, except that each user requires a unique identifier, generally in the form of a cookie. Therefore, a first-time visitor has to make a round trip back to the origin is order to fetch this unique identifier, increasing page load times for first-time visitors to the site. With our Dynamic Caching technology, we can predictively request a series of responses containing unique identifiers and store them in a short-term queue on our service. As first-time visitors come to a site, one of these responses in the queue is issued without the need to go to the origin server. Meanwhile, a new identifier is requested from the origin to replace the one depleted and is added to the queue in advance of future first-time users.

Instart is the only company to provide this unique solution to its customers. By enabling a better first-time visit for shoppers, companies will have a significant advantage and reduce the high drop-off rate typically experienced with first-time visitors.

For details, see the Dynamic Caching section.

Image Transcoding with SmartVision

Transcoding JPG and PNG images in place allows a reduction in image data size by removing unneeded metadata, applying improved compression methods when possible, and preparing images. The overall data transfer per image is smaller. JPG and PNG images can also be transcoded to WebP and JPEG XR files, which offers even better data size reduction in Google Chrome (WebP) or Microsoft Internet Explorer 10 and above (JPEG XR).

For more information see the Image Transcoding section.

Image Adaptation

Image Adaptation uses our image processing capabilities to apply a variety of image processing operations to images in JPG, PNG, GIF and animated GIF formats. We can

  • resize to a specific pixel size, a relative percentage of the original image, or a maximum or minimum dimension
  • crop images to a specific size from a specified location relative to the image's borders
  • filter images to grayscale or black and white
  • sharpen images to reduce apparent blurriness
  • add a border of a specified color and size
  • chain any of these operations (processed in the order specified)

This allows you to store a single high-resolution image on a backend origin web server and then process images as needed when they are delivered through our service. This allows, for example, sending smaller images to mobile and tablet devices with smaller screens and providing thumbnails for larger images.


Images for Image Adaptation must be JPG, PNG, GIF, or animated GIF only.

Images can be processed using simple resize or cropping commands that are added to the query string of an image's request.

For details, see What is Image Adaptation?