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How to Use an HTML to PDF API to Generate PDFs in Your Web Application

Here's how to use an HTML to PDF API to generate professional high-quality PDF files for your web application.

January 13, 2023

6 min read

Dan Cucolea

Dan Cucolea

Converting HTML to PDF files is a rather common functionality among web applications.

Whether you need to generate an invoice for an e-commerce store, a bank statement, or even convert an article to a downloadable PDF, using an API is the best method to achieve all these because:

  • You can save a lot of time that would otherwise be spent creating your own conversion service

  • You don't have to worry about debugging your conversion code

  • You can implement this functionality regardless of your stack.

In this article, you will learn how to use an HTML to PDF API to generate professional high-quality PDF files.

What is an HTML to PDF API?

An HTML to PDF API is an application programming interface (API) that allows developers to convert HTML content into PDF documents. These APIs accept either an HTML file (including CSS and JavaScript) or an URL and generate a PDF document.

Some HTML to PDF APIs can also output files in various different formats, like PNG, JPEG, SVG, or WEBP. Even though you might not need this functionality right now, you should plan ahead and get familiar with an API that can generate files in various formats.

How do HTML to PDF APIs work?

Most HTML to PDF APIs render a webpage or HTML file before capturing a screenshot and exporting it as a PDF document. You should keep in mind that some APIs struggle to render JavaScript or CSS correctly, so before you pick a service, make sure it can:

  • Correctly render modern frameworks like Bootstrap and Flexbox

  • Render and capture full page screenshots

  • Hide specific elements by selector

  • Allow you to select the page size of the PDF

  • Change the documents' margins, orientation, and scale

  • Create and append headers and footers to the generated document

  • Block ads and automatically accept cookies or hide cookie banners

One of the best HTML to PDF APIs on the market is Urlbox. It comes packed with all the above-mentioned features, plus more, so you can be sure your final PDF documents will look exactly as you want them.

How to convert HTML to PDF with the Urlbox API

Converting an HTML file or URL to a PDF document with Urlbox is extremely straightforward, as all you have to do is write a simple request like this:\[API\_KEY\]/pdf?

The above example works with a live URL, but if you want to convert HTML code (with inline CSS and JS), you can simply switch the last parameter, "url=", with "html=" and append the actual code.

Here's an example of how it would look like:\[API\_KEY\]/pdf?html=Enter%20your%20HTML%20to%20be%20rendered%20e.g.%20%3Chtml%3E%3Chead%3E%3C%2Fhead%3E%3Cbody%3E%3Ch1%3EMy%20HTML%3C%2Fh1%3E%3C%2Fbody%3E

In addition, you can configure how the PDF will look by using one or more of the (/docs/options#pdf-options)PDF options Urlbox has available:

  • pdf_page_size
  • pdf_page_width
  • pdf_page_heigh
  • pdf_margi
  • pdf_margin_to
  • pdf_margin_righ
  • pdf_margin_botto
  • pdf_margin_lef
  • pdf_scal
  • pdf_orientatio
  • pdf_backgroun
  • disable_ligature
  • media

How to allow users to download a PDF document generated from HTML

Chances are you'll want users to be able to download the generated PDF document. The Urlbox API has a built-in functionality you can use to automatically create a download link for all the documents you create.

All you have to do is append the "download" parameter to the request URL. Here's an HTML snippet that will create a download link for a PDF document named "my-document.pdf":

  >Download PDF</a

The above example works for live URLs, but you can also generate a PDF from an HTML file and automatically create a download link for it.

Here's another example of how that would look like:

  >Download PDF</a

It's important to keep in mind that your API key is embedded in the request URLs presented above. This means that anyone can potentially start using your key, so if you plan on implementing Urlbox in your web app, then you have to use an authenticated request format, as explained in the official documentation.

How to convert HTML to PDF with any programming language

As mentioned before, you can use a simple request URL to generate a PDF document from an HTML file or URL, but you can also seamlessly integrate Urlbox with your web app by writing a few lines of code.

Here are a few examples covering the implementation of an HTML to PDF functionality in a web app for major programming languages:

These are just a few examples, but you can always contact the Urlbox team if you need help with any other programming language.

You can try Urlbox for free for 7 days, after which you can upgrade to any paid plan starting at just $19 per month. The Starter plan lets you generate up to 2,000 PDF documents monthly (including PNG, JPEG, or any other supported image type).

Other tools and APIs to convert HTML to PDF

You can convert an HTML file to a PDF documentin multiple different ways. However, most tools and APIs either struggle to correctly render the HTML code or simply generate low-quality PDFs. It's up to you to decide which tool is better suited for your specific use case.

Here's a list of other methods, tools, and APIs you can try:

  • wkhtmltopdf Library- You can create your own microservice using a library, but this means extra development hours, not to mention the final PDF will most likely be of poor quality.
  • PDFmyURL API- This is another type of API that allows you to convert URLs to PDFs. It's not clear if it works with HTML files.
  • HTMLPDFAPI - An API built specifically to convert HTML files to PDF documents. It's a bit pricier than the other solutions, plus we are not sure how well it can render complex web pages.

It's important to try multiple tools before you settle on a specific one so you can get a feel of how they work and if they are exactly what your project needs.

You can start with Urlbox, perhaps the most comprehensive yet easy-to-use HTML to PDF API.

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