Monospaced fonts (where every character has the same width) used to be confined to code editors and terminal outputs. Now they’re a common choice for branding — especially for tools, dashboards, and apps where numerics matter.
The two most popular open-source mono fonts in modern design systems are JetBrains Mono and IBM Plex Mono. They look superficially similar but signal different things, and the choice matters once a brand starts living across decks, documents, and code.
JetBrains Mono
Designed by: JetBrains (the IDE company) Signal: indie hacker / developer tool / “I build things”
Strengths
- Extremely clean for displaying code
- Strong “builder” vibe — recognisable to developers immediately
- High personality, distinct character shapes
- Excellent programming ligatures (
!=,=>,<=) - Free, open-source (Apache 2.0)
Where it fits
- Dev-focused tools and apps
- Indie hacker product pages
- Apps whose primary audience is engineers
- Any product positioning itself as “by builders, for builders”
IBM Plex Mono
Designed by: Bold Monday for IBM Signal: institutional / corporate / structured intelligence
Strengths
- More neutral and institutional than JetBrains Mono
- Part of a full type system: IBM Plex Sans + Serif + Mono all designed to work together
- Excellent for presentation decks, board materials, finance documents
- Pairs well with the Sans variant for body text within the same brand
Where it fits
- Apps with mixed-audience users (not just engineers)
- Brands that need to scale into formal documents and decks
- Finance, analysis, and operations tools
- Companies positioning themselves as serious operators rather than experimental tinkerers
How to choose
A useful rule:
Use JetBrains Mono when the audience is developers. Use IBM Plex Mono when the audience is operators.
A developer-targeted tool (a CLI, a dev IDE, a code analysis platform) reads more credibly in JetBrains Mono because its users will recognise the typeface and feel at home. A finance tool, a business dashboard, or a content platform reads more credibly in IBM Plex Mono because it doesn’t pre-announce “this is by and for hackers.”
When to mix
If a portfolio of apps spans both worlds — a developer tool and a finance tool from the same person or studio — IBM Plex Mono is usually the better master font with JetBrains Mono used as a sub-identity for the dev-facing products.
The opposite (JetBrains Mono as the master, IBM Plex Mono as the variant) tends not to work as cleanly because JetBrains Mono is more visually distinctive and harder to neutralise.
Other monos worth knowing
- Geist Mono (Vercel) — minimal, modern, popular among next-gen indie hackers
- Fira Code — code-focused, with extensive ligature support
- Roboto Mono — Google’s mono; neutral and ubiquitous
- JetBrains Mono Light — same family but with thinner weights, sometimes better for body text
Practical loading
For web apps, both JetBrains Mono and IBM Plex Mono are hosted on Google Fonts and CDNJS. For native apps, both ship as open files (.ttf / .otf / .woff2). Both are free for commercial use with no attribution required in the rendered output.