JetBrains Mono

A monospace font designed by the JetBrains team specifically for staring at code all day. If you spend 8+ hours reading code and haven't thought about your font choice, this might be the easiest quality-of-life upgrade you can make. JetBrains Mono is optimized for code readability: increased letter height, distinct characters (zero vs O, one vs lowercase L), and functional ligatures that turn common code symbols into single glyphs (!=, =>, ->, ===). The ligatures are the standout feature. Instead of two characters side by side, you see a single visual symbol. Some developers love this, some hate it. Try it for a week before deciding. Every major editor supports it: VS Code, JetBrains IDEs, Sublime, Vim, Emacs.

Completely free under SIL Open Font License. Use it anywhere: personal, commercial, modified, redistributed. No restrictions. If ligatures annoy you, Fira Code offers similar features with a different aesthetic. If you want something with no ligatures and maximum readability, IBM Plex Mono or Berkeley Mono (paid, $75 one-time) are excellent. Inter Mono is a newer option gaining traction for its clean modern look.

The catch: font preference is deeply personal, and ligatures aren't for everyone. It's a font. Install it, try it, keep it or don't. Zero risk.