The choice between synchronous and asynchronous code is all about the distribution of processes. In synchronous programming, tasks are performed one at a time as a sequence of actions. Asynchronous code allows running processes simultaneously. It enables you to offload work and complete several operations in parallel.

When it comes to creating documentation and reports with HTML to PDF generators, you might need both synchronous and asynchronous code. Everything depends on the scope and complexity of rendering. Synchronous code is usually set by default since it supports basic HTML to PDF file conversion. It’s enough to render a two-page invoice or generate an electronic bill. Asynchronous code allows more complex conversion, like a report loaded with high-resolution images or a huge batch.

If you manage a tech team, the choice of the programming approach for a PDF generator can be confusing. That’s why we want to share our knowledge on the use of synchronous and asynchronous code for documentation creation. Read on for the main points to consider.

What Is Automated HTML to PDF Documentation Creation and When Do You Need It?

Automated HTML to PDF documentation creation is the use of PDF generators to automate document rendering. The source code of an HTML file is automatically converted to PDF with all the necessary fields and HTML head metadata. The conversion happens based on real-time triggers, and the result is instantly available.

PDF Documentation Creation

HTML to PDF rendering is mostly used by businesses and software vendors. They need it to generate PDF invoices, reports, bills, software documentation, and other documents. To avoid the troublesome development of rendering capabilities, they adopt PDF generators as an API. It ensures quick integration, support, and security.

Example of HTML to PDF Generator Use

Imagine you own an online store. At the checkout, a person might want to download the confirmation of payment and shipping. People often do that to be sure they won’t lose important information.

Since PDF is the most convenient format for official documentation, you will need to provide documents in PDF. As the source content is created in HTML, your web portal must automatically convert HTML to PDF to display the loaded data. It must also enable users to retrieve the generated file in PDF if they want to download it. That’s when you use HTML to PDF conversion.

The approach applied for document processing (synchronous vs. asynchronous code) will depend on the complexity of rendering operations. You are free to choose any software development method as long as it meets your tech and business needs. Find out more about synchronous vs. asynchronous code below.

Learn How to Use PDF Generators in Digital Publishing

Synchronous vs. Asynchronous Code

Synchronous code means that you need to wait for the processes to finish before moving to another task. It’s a linear process when operations happen one by one. Asynchronous functions allow moving to the next task before the previous one finishes. Asynchronous programming enables your software to handle multiple requests simultaneously.

Currently, both synchronous and asynchronous code is used in software development. Programming languages are by default synchronous and are single-threaded, but many of them allow you to execute async functions. So the choice of the approach basically depends on the number of requests you need to run and their dependency.

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Synchronous Code: Uses, Pros, and Cons

In the synchronous programming model, operations happen sequentially, one after one. The software moves to the next step only after the current operation has completed execution. It means that long-running operations block the program until they are completed.

Therefore, we recommend using synchronous code to run simple operations with a limit of up to 60 seconds. There is no point and benefit in writing asynchronous code for basic computations like a single document rendering. You should also use synchronous programming to update dependent records since it helps to keep them synchronized. At the same time, synchronous code is not suitable if you seek efficiency or execute a large number of iterations.

Asynchronous Code: Uses, Pros, and Cons

In the asynchronous programming model, several operations happen at the same time. You can perform the task without blocking the main process (e.g., the use of the web portal). The parallelization of processes allows executing independent operations. The software doesn’t wait for the end of the previous operation before starting another. It cuts page load time and allows you to complete more complex tasks more efficiently.

That’s why asynchronous code is effective in processing independent data since it ensures better UX and performance. It’s also great if you need to preload data. The asynchronous model is not suitable for dependent tasks.


Generally, there is no point in overcomplicating things that can be made simple. When synchronous code satisfies your needs and performs the necessary tasks, you shouldn’t make asynchronous loops. Asynchronous code is not suitable for all cases.

So the key task before using synchronous vs. asynchronous code for rendering is to evaluate the rendering complexity and pick the best approach. Understand the dependencies between processes to identify which are independent and which must be executed as a result of other processes.

How PDF Generators Synchronously Render HTML to PDF

Synchronous rendering in PDF generators can cover most of your rendering needs as a business. Its time limit is enough to render invoices, bills, agreements, emails, and other commonly used documents. PDF generators that run synchronously convert HTML files to PDF one by one. For example, when a healthcare portal user wants to see their test results, they click the corresponding button, and the PDF generator creates a report. Since the content of the reports doesn’t take too much memory, it can be created synchronously.

How PDF Generators Asynchronously Render HTML in Place to PDF

When rendering is too resource-consuming, it’s better to asynchronously render HTML in place. Asynchronous code allows rendering several elements of content simultaneously and reduces the wait time. That’s why asynchronous functions are preferred for documentation creation when the content is very large or complex.

html to pdf

As a rule, if you use a PDF generator as an API, you can set it both to synchronous and asynchronous rendering. Minor changes in the source code allow changing the method of request execution.

Learn About User Role Management in PDF Generator APIs

Render PDF Generator for Customized PDF Documentation Creation

Render is a PDF generator API provided as one of Inkit’s core products. It enables you to integrate your current software solution with HTML to PDF rendering capabilities. Render can process a simple invoice and a batch of reports with high-resolution images with the same ease. You only need to change several settings and values.

Apart from easy documentation creation, Inkit’s Render is also renowned for its extensive user roles. You can choose who creates documents, views them, has the right to assign roles, etc. It significantly enhances rendering software management and data security since different teams have different access levels.

View our user guides to learn more about how Render works, or contact us to get the demo.

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