Variable Fonts With Next.js

Next.js has a font module load local and google fonts but their documentation isn’t clear on how to load variable local fonts properly.

I have tried to use Inter variable font on my website and waned to share how I did it.

import localFont from "next/font/local";

export const fontSans = localFont({
  src: [
    {
      path: "Inter-4.0/InterVariable.woff2",
      style: "normal",
    },
    {
      path: "Inter-4.0/InterVariable-Italic.woff2",
      style: "italic",
    },
  ],
  weight: "100 900",
  display: "swap",
  variable: "--font-sans",
  declarations: [
    {
      prop: "unicode-range",
      value: "U+0020-007F",
    },
  ],
});

Setting the weight: "100 900" was important here. This is not documented clearly in Next.js documentation, and without it all my font weights were being synthesized from single regular weight.

From here, the documentation is pretty clear. You just add fontSans.variable to className on body tag, prepend var(--font-sans) to your font-family and you are set.

The code snippet in this post also uses a unicode-range. To read more about it you can read this post.