feat: full Nerd Font glyph coverage and custom font-family option for the web terminal

Start with site/src/theme/fonts/coder-terminal-symbols.css and site/src/theme/constants.ts, then read the per-user terminal font picker from #17257. Determine whether the change will extend the bundled symbol fallback, add a custom font-family setting, or both. Done means the embedded terminal renders the requested Nerd Font glyphs and supports the selected custom family when implemented.

Summary

A customer's developers want to use JetBrains Mono Nerd Font in the embedded web terminal, primarily for Neovim/LazyVim and other icon-heavy TUI tools (eza, lazygit, etc.). This is not achievable through Coder configuration today.

Current state

#15024 was closed by #17257, which added a per-user terminal font picker (Geist Mono, Fira Code, JetBrains Mono, Source Code Pro, IBM Plex Mono). Separately, site/src/theme/fonts/coder-terminal-symbols.css bundles "Coder Terminal Symbols", a subset of Symbols Nerd Font Mono v3.4.0 that is appended to every terminal font stack in site/src/theme/constants.ts.

However, that fallback only covers the Powerline range (U+E0A0, U+E0B0-E0BF). Powerline prompts render correctly, but the rest of the Nerd Font private-use ranges (devicons, Font Awesome, Material, Codicons, Octicons, etc.) do not, so Neovim/LazyVim, eza, lazygit and similar tools show missing glyphs. Recent comments on #15024 (April/June 2026) report the same problem.

There is also no way to specify a custom or locally installed font family; the setting is a closed enum (codersdk.TerminalFontName).

Requests

Either or both of the following would resolve the customer's use case:

1. Extend the bundled symbol fallback to the full Nerd Font glyph set (or at minimum the commonly used ranges: U+E000-F8FF, U+F0000-FFFFF). Since Coder Terminal Symbols is already in every font stack, this fixes icon rendering for all five listed fonts with no user configuration. Tradeoff: the full Symbols Nerd Font Mono woff2 is a few MB; font-display: swap and lazy loading only on terminal pages should mitigate this.

2. Add a custom font-family option in Appearance settings (and/or a deployment-level setting), so users or admins can name a locally installed font such as JetBrainsMono Nerd Font Mono. This would let users opt into a fully patched font without Coder bundling it.

Option 1 is preferred as it benefits all users out of the box.

Workaround today

Overriding the terminal font via browser font settings or a user stylesheet targeting .xterm. Per-user, fragile, and not something we can recommend as supported.

Filed by @ericpaulsen on behalf of a customer. This issue was drafted with Coder Agents.