Here are some useful resources if you're trying to set up a favicon for your Next.js project.

• Complete Favicon Generator: In the end, I used this generator in Figma. Thank you, Ernest Ojeh!

• Metadata Files API Reference (favicon, icon, and apple-icon) from the official Next.js documentation. I found it not very clear and spent time asking Phind to help me find a solution.

• RealFaviconGenerator: It promises to generate perfect favicon files in 5 minutes. It's doing a good job, but many files were missing.

• Favicon checker: Use this tool to check if everything is working properly. It has some requirements, and I deployed without satisfying all of them.

Here's my working code snippet:

export const metadata: Metadata = {
  title: "Growthlog by Tomas Laurinavicius",
  description:
    "Welcome to Growthlog by Tomas Laurinavicius, a founder, marketer, designer, and writer from Lithuania, based in Spain.",
  manifest: "/manifest.json",
  icons: {
    shortcut: { url: "/favicon.ico", type: "image/x-icon" },
    icon: [
      { url: "/favicon.ico", type: "image/x-icon" },
      { url: "/favicon.svg", type: "image/svg+xml" },
      { url: "/favicon-16x16.png", type: "image/png", sizes: "16x16" },
      { url: "/favicon-32x32.png", type: "image/png", sizes: "32x32" },
      { url: "/favicon-96x96.png", type: "image/png", sizes: "96x96" },
      {
        url: "/favicon-192x192.png",
        type: "image/png",
        sizes: "192x192",
      },
    ],
    apple: [
      { url: "/favicon-57x57.png", sizes: "57x57", type: "image/png" },
      { url: "/favicon-60x60.png", sizes: "60x60", type: "image/png" },
      { url: "/favicon-72x72.png", sizes: "72x72", type: "image/png" },
      { url: "/favicon-76x76.png", sizes: "76x76", type: "image/png" },
      {
        url: "/favicon-114x114.png",
        sizes: "114x114",
        type: "image/png",
      },
      {
        url: "/favicon-120x120.png",
        sizes: "120x120",
        type: "image/png",
      },
      {
        url: "/favicon-144x144.png",
        sizes: "144x144",
        type: "image/png",
      },
      {
        url: "/favicon-152x152.png",
        sizes: "152x152",
        type: "image/png",
      },
      {
        url: "/favicon-180x180.png",
        sizes: "180x180",
        type: "image/png",
      },
    ],
  },
};