I’m building a typesetting engine for a living (speedata Publisher). People keep asking me “why not just use Typst?” or “isn’t WeasyPrint good enough?” and I never had a good answer with real numbers. Just gut feeling. So I decided to actually measure it.

I set up a simple benchmark, same document with all six tools. And what I learned was maybe not what I expected.

The setup

The task is simple: a mail merge. You have an XML file with name and address records, you fill in a letter template, and you get a PDF out. One page per letter, with a logo, sender info, recipient address, and some body text. Nothing special, really every tool should be able to do this.

I have rebuilt the macOS packages of the speedata Publisher and released them as version 5.2.1. The Windows and Linux packages remain at 5.2.0, because the changes are macOS-specific.

This post is a short write-up of what broke, how I debugged it, and which tools I used along the way. If you ever need to get a macOS command line tool notarized, this might save you some time (or at least a bit of frustration).

Big Improvements Under the Hood

We’re happy to announce a new development snapshot of the speedata Publisher! This release comes with major internal improvements, cleaner architecture, and a bunch of small but meaningful user-facing enhancements.

Rewritten XML Parser

The XML parser has been completely reimplemented in Go, with a stronger focus on correctness, performance, and test coverage. It now keeps track of the originating file when using XInclude, which makes debugging and error reporting much easier.

It has been a while since my last post on this blog. This time I would like to introduce a project that is a bit different in scope but technically closely related to the speedata Publisher: billingcat – an open-source application for invoicing and simple customer relationship management.

I have been playing with electronic invoices (especially the German and French ZUGFeRD/Factur-X format) for a while now. The speedata Publisher has support for ZUGFeRD since 2017.

The next step is to make (my other PDF generation software) boxes and glue work with electronic invoices. For that, I use the new command line interface for boxes and glue (which I will describe in a future blog post).

There only a few things that need to be done to make this work:

Almost five years after releasing version 4.0 of the speedata Publisher, it is time for version 5.0. This is a short announcement, since most changes have been covered before.

The speedata Publisher looks the same since its beginning, but there have been major changes under the hood since version 4:

• Integration of HarfBuzz for left to right and right to left text layout, even mixed (bidirectional) typesetting. Support for all kinds of fonts and font features.
• Full accessibility support.
• A rewritten XML and XPath 2.0 parser.
• Attachment of ZUGFeRD invoices.
• Greatly enhance enhance various subsystems such as HTML, MetaPost integration and paragraph builder.
• SAAS available with the speedata Pro plan.

There have been a few entries here in the blog (4.16, 4.18, 4.20)

Don’t worry, the speedata Publisher will not gain any half-baked, annoying artificial intelligence features. This post is about chatting with some of the more famous AI chats (ChatGPT, Google Gemini, DeepSeek). I have tried to find out how good these AI chats know the speedata Publisher and if they can help users to generate a layout.

There is still a long road ahead, but read on. A big warning upfront: None the following outputs work. Do not use them. I post abbreviated transcripts of the chats.

The following text is written from a German perspective. This should apply to all parts of the European Union, although with likely differences in other countries.

Since the beginning of 2025, all companies in Germany have had to send and receive electronic invoices (with overriding deadlines and a few exceptions). This affects me too, so I asked myself (out of curiosity), what is an electronic invoice and how can I process it?

After more than half a year, 150 commits and 40 minor releases, I have now published version 4.20, which is hopefully the last stable version before the “big five”.

I have created JavaScript bindings for boxes and glue. These bindings are made with goja. Let me show you an example: