A ligature is when a special combination of one or more characters is joined together to form a new symbol. Look closely at “tt” characters below.

The pitter-patter of the rain was of little matter.

Some fonts will combine the crossbars of the two “t” characters (instead of having a tiny gap between them) to make the word look more cohesive. If you were taught traditional cursive handwriting, you might have been taught to combine the crossbars of double Ts exactly like this.

Other common programming ligatures include:

It’s a matter of personal taste², but many programmers—myself included—find that these ligatures make code look more meaningful and easier to parse.

Now, on to some actual programming fonts…

Going as far back as 2012, Hasklig was one of the earlier programming fonts to use ligatures for code. It used the beautiful Source Code Pro as its base font, but with added ligatures that were mainly geared towards code written in Haskell.

Sadly, this meant that it did not include that many ligatures for general programming. It also hadn’t received any major updates for a long time. For these reasons, I never really considered using Hasklig, despite the good looks of Source Code Pro.

Fira Code was the first real experience I had with programming ligatures. I used it heavily for more than 4 years. It also has a solid foundation, being based on the monospaced variant of Mozilla’s Fira type family, Fira Mono. Due to its strong community support, it’s easily one of the most popular programming fonts out there and I would have no problem recommending it to any programmer.

I was happy until I discovered that Fira Mono didn’t have a dedicated italic variant. This deficiency was carried over into Fira Code too, making it difficult for me to show true italics in Emacs, especially when using Org mode.

Microsoft’s response to Fira Code was to create Cascadia Code. It was developed alongside Windows Terminal³ and was intended to improve both programming and command line experiences. This can be seen in its official “PL” variant which has embedded Powerline symbols in addition to many programming ligatures.

I really wanted to like it, since it had such a positive community around it from the get go. Unfortunately it suffered the same lack of true italics as Fira Code/Mono did. I also found that it lacked the readability that I was used to with Fira Code. This was doubly important when working in text documents such as Org mode or markdown where I’d have to read and review actual sentences and paragraphs. I couldn’t really put my finger on it, but it just seemed a little clunky to me.

Iosevka is a procedurally generated font. It’s built by running code (Node.js/JavaScript in this case) which allows for a ton of customization. The current release has no fewer than 21 different prepackaged variants to choose from, each with subtle changes that were inspired by other fonts. As a user you can really go wild here—even if none of the 21 variants suit your fancy, you can clone the repository, configure some parameters, then build a totally customized font to call your own.

I have to admit, I really loved the idea of Iosevka: a coding font built with code. I used it happily for 2 solid weeks, but ultimately gave up on it because of mysterious performance issues that I only encountered in Emacs⁴.

Another issue that put me off using Iosevka everywhere was that of its design philosophy:

The Iosevka’s monospace family is provided in a slender outfit by default: glyphs are exactly 1/2em wide. Compared to the competitors, you could fit more columns within the same screen width.

— https://typeof.net/Iosevka/

This was quite a bit more narrow than I was used to, so I used the Extended variant to get slightly wider characters. It was OK, but still a little cramped.

During my research, I had seen JetBrains Mono mentioned every now and again. I had initially dismissed it thinking that it was more focused on JetBrains software or its users. Turns out, not at all!

JetBrains Mono ticked every box for me:

• True italics
• Great readability
• General purpose programming ligatures
• No performance issues in Emacs

And even ticked a few more boxes that were on my nice-to-have list:

• A variety of weights
• Vertically centered asterisk
• Zero with a central dot instead of a slash
• Clearer programming ligatures than some of the competition
• Scripted f and y for true italic feel

JetBrains Mono isn’t without its critics though. Some say that the increased x-height isn’t proven to increase readability, and that the “functional construction” of the glyphs makes the letters look too similar, which supposedly decreases readability.

But I’ve been using the JetBrains Mono Semi Light in Emacs for a while now. No matter what I throw at it, from huge blocks of text in Org mode to dense chains of lambdas in TypeScript, it gets out of the way and lets me focus on my work. That’s what’s really important. Count me as a very happy user.

Of course, your needs will be different to mine. Despite the heated debate about ligatures or no ligatures, serifs or sans-serifs, Consolas or Operator Mono, there’s one point that everyone agrees on: the font you choose for programming is entirely up to you.

So what suits you? Do you like ligatures? Do you hate them? Do you prefer a condensed font? Do you need true italics?

Try the suggestions above, or use them as a starting point to discover your own preferences. There are actually so many more programming fonts that I just haven’t had time to cover.

Go forth and personalize your coding experience. Make your editor yours.