Posted by & filed under HTML to PDF API, HTML to PDF SDK.

As you may know we have two different ways of creating PDFs from your application – our HTML to PDF API and our HTML to PDF SDK.Since not everyone is so familiar with the terms API and SDK, we’ll try to explain them in this post and look at the differences.

The term API is short for Application Programming Interface and is a protocol intended to be used as an interface by software components to communicate with each other (see Wikipedia). So basicly it’s a set of rules that describes how two or more ‘systems’ communicate with each other. Wikipedia goes on to state that it can take many forms and be simple or elaborate.

The term SDK is short for Software Development Kit and is typically a set of software development tools that allows for the creation of applications for a certain software package, software framework, hardware platform, computer system, video game console, operating system, or similar development platform (see Wikipedia). So it means you get tools that allow you to create stuff fast.

Our interpretation of API vs SDK

When we were developing our services we wanted to make sure that they were easy-to-use and quick to deploy no matter what. But we also realized that some people want to have more freedom and others want to lay down in a made bed, that’s warm and cosy. So we made our HTML to PDF API as a basic definition that allows you to generate a PDF from a URL by just sending a HTTP request and we made our HTML to PDF SDK as a fully equipped PHP library that not only does the HTML to PDF conversion, easily adds all kinds of options, but also takes away your worries about error handling, displaying PDFs and what not.

Both the API as well as the SDK are packed with functionality in terms of conversion, although the SDK has a lot more and is one of the most (if not THE most) complete on the market.

Functional differences

So what are the differences in functionality of the API compared to the SDK? Well, let’s make a little list then… But before we start with the list you should know the SDK is only available in PHP right now. This is because it’s a library, which spans quite a few lines of code and has to be maintained, tested etc on an ongoing basis. We’ll be adding different languages in the future, but for now we only offer it in PHP. The HTML to PDF API on the contrary works in ALL programming languages and our site contains examples in the most used programming languages.

Now back to the list. What can you do with the HTML to PDF API and what can you do with the HTML to PDF SDK?

With the API as well as the SDK you can do the following (mind you – non-exhaustive list):

  • convert any URL to PDF
  • use CSS2, quite some CSS3, many character sets – all in high quality
  • use all standard page formats as well as any custom format you can think of
  • have the ability to create single page PDFs
  • use custom margins
  • pre-define a header and/or footer
  • use PDF encryption, password protection and rights management
  • use an image as watermark and control positioning, rotation and opacity

That’s quite a bit, isn’t it? Well, the SDK on top of that allows you to do the following:

  • convert raw HTML, local files and custom forms with parameters (which we can build for you)
  • control PDF rights management in more detail
  • use a text in any font, size and color as a watermark
  • easily control what to do with the resulting PDF – whether to display it inline or as attachment or save it
  • build the code in your application quickly and with built in error checking with the easy-to-use PHP library

It’s a also noteworthy that from a technical perspective the HTML to PDF API works over HTTP GET, while the HTML to PDF SDK sends all data over HTTP POST. The HTTP GET request is basicly a long URL that incorporates all parameters.


Now the most important question of all is – do they both make great PDFs? And the simple answer is – YES THEY DO! The how it works section has a little showcase of PDFs that we make with our service and if you’ve ever converted one on the homepage you know that our output is top notch. After all – we offer a 30 day 100% money back guarantee on all paid subscriptions!

Please check out our HTML to PDF API section or HTML to PDF SDK section if you want to know all about the specifics and how to use these wonderful products. If you feel like signing up – GO AHEAD!

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