Let's be real for a second. Nobody wakes up in the morning excited to write PDF generation code.
It usually starts as a quick task. Your project manager drops by and says, "Hey, can we just add an 'Export to PDF' button for these invoices?" You nod. It sounds like a two-hour job.
Three days later, you're still sitting there at 2 AM, trying to figure out why your table rows are splitting in half across pages or why the custom font works on your local machine but turns into garbage on the server.
I've been down this rabbit hole too many times. So, instead of grabbing the first library I found on Google, I decided to actually sit down and test the three big players in the .NET space to see which one respects my time the most.
Here is the breakdown of iText 7, QuestPDF, and IronPDF.
The Mental Model: How They Work
The biggest difference isn't the syntax; it's the philosophy.
iText is old-school. It treats the PDF like a canvas. You have to tell it exactly where to draw every line. You are basically manually calculating coordinates. It gives you control, sure, but it feels like building a house by laying every single brick yourself.
QuestPDF is the new kid on the block. It uses a "Fluent API." If you like strictly typed C# code, it looks clean. But you are still "coding" the visual layout. You have to learn their specific language to make things look right.
IronPDF takes a different approach. It assumes you already know how to design a document because... well, you know HTML. It literally embeds a Chrome browser engine. You give it HTML, it gives you a PDF.
The "Just Get It Done" Test
How hard is it to just get a simple file on the disk?
iText 7 makes you work for it. You need to juggle a PdfWriter, a PdfDocument, and a Document object just to write one sentence.
using iText.Kernel.Pdf;
using iText.Layout;
using iText.Layout.Element;
using var writer = new PdfWriter("hello.pdf");
using var pdf = new PdfDocument(writer);
using var document = new Document(pdf);
document.Add(new Paragraph("Hello World"));
QuestPDF is cleaner, but you still have to build the whole tree structure manually.
Document.Create(container =>
{
container.Page(page =>
{
page.Content().Text("Hello World");
});
}).GeneratePdf("hello.pdf");
IronPDF just gets out of your way.
var renderer = new ChromePdfRenderer();
renderer.RenderHtmlAsPdf("<h1>Hello World</h1>").SaveAs("hello.pdf");
The Maintenance Headache
This is where things usually fall apart. Writing the code the first time is easy. Changing it six months later is the problem.
Picture this: The Marketing team decides the logo needs to be 20% bigger and the font should be "Open Sans."
If you used iText or QuestPDF, you are in for a bad time. You have to open the code, find the lines calculating the image size, realize the bigger logo messes up the text padding, recalculate the layout math, find the font file, and recompile the whole app.
With IronPDF, I just opened the HTML template string. I changed <img width="100"> to <img width="120"> and pasted the Google Fonts link in the header. It took me about three minutes. I didn't even have to touch the C# logic.
What About Debugging?
Debugging PDF layouts is usually a nightmare. You make a change, run the app, open the PDF, see it's wrong, close it, and repeat. It’s a blind process.
Since IronPDF uses HTML, I realized I could just design the invoice in Chrome. I built an HTML file, right-clicked "Inspect Element," and tweaked the CSS until it looked perfect.
Once I was happy, I just copied that HTML into my C# project. The PDF looked exactly like the browser. That feature alone probably saved me ten hours of work.
Let's Talk Performance (The Honest Truth)
I ran a quick benchmark on my laptop (i7, 16GB RAM) to generate 100 invoices. I'm not going to sugarcoat the results. But to be fair, we have to look at two types of "speed": how fast the code runs, and how fast you can write it.
Here is the full picture:
| Metric | iText 7 | QuestPDF | IronPDF |
|---|---|---|---|
| Runtime (100 files) | ~1.2 seconds | ~2.5 seconds | ~8.5 seconds |
| Coding Time (Initial) | ~4 Hours | ~2.5 Hours | ~15 Minutes |
| Maintenance Effort | High | Medium | Low |
Yes, IronPDF is slower at runtime. There, I said it.
It has to spin up a headless web browser instance, which takes more RAM and CPU than just writing binary bytes like iText does.
But here is the question: Does it matter?
Unless you are generating 1,000 documents per second for a high-frequency trading platform, probably not. For generating an invoice or a report? The user won't notice if it takes 80ms or 800ms.
But you will definitely notice if it takes you 4 hours to code the template instead of 15 minutes.
IronPDF trades some cheap CPU cycles to save your expensive development time. In my book, that is a trade worth making every single time.
A Real World Example
I actually had to build an E-commerce receipt recently. It needed a dynamic QR code for returns and a table with "zebra striping" (alternating colors).
I tried doing it the "code way" first. I had to find a separate library just to generate the QR bitmap and convert it. Then I had to write a loop with i % 2 == 0 logic just to color the table rows. It felt clunky.
When I switched to the HTML approach, it was trivial.
-
QR Code: I just used an
<img>tag pointing to a QR API. -
Striping: I added a simple CSS rule:
tr:nth-child(even) { background-color: #eee; }.
Done.
The Verdict
Look, tools are just tools. Pick the right one for the job.
- If you need raw speed and are manipulating existing PDFs? Go with iText.
- If you hate HTML and love strictly typed C# structure? QuestPDF is actually pretty nice.
- If you want to finish the task by lunch and never worry about layout math again? Use IronPDF.
Personally, I'm done drawing rectangles with code. I'll stick to HTML.
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