Framework

Rails Favicon Generator

Rails expects the favicon to go through the asset pipeline. Put the files under app/assets/images and declare them with favicon_link_tag in the application layout so production fingerprinting keeps working.

Generate the icon set Check an existing site

Asset pipeline, not public/ alone

Rails 8 defaults to Propshaft. Files under app/assets/images are fingerprinted on precompile and served from /assets/... in production. The favicon_link_tag helper resolves the logical name to that digested path, which is why a bare /favicon.ico in public/ and a helper-managed icon are different strategies.

public/favicon.ico still works as a legacy fallback for clients that request the root path without reading link tags. For the rest of the set (PNG sizes, apple-touch-icon, manifest) use the helpers in the layout so digests stay correct after each deploy.

Where the files go

my-rails-app/
- app/
  - assets/
    - images/
      - favicon.icoadd
      - favicon-32x32.pngadd
      - apple-touch-icon.pngadd180x180
      - icon-192.pngadd
      - icon-512.pngadd
  - views/
    - layouts/
      - application.html.erbhelpers go here
- public/
  - favicon.icoaddoptional root fallback
  - site.webmanifestadd

Propshaft copies everything under app/assets into public/assets on precompile. The layout should reference logical names, not the digested filenames.

application.html.erb

<!DOCTYPE html>
<html>
  <head>
    <title><%= content_for?(:title) ? yield(:title) : "My app" %></title>
    <meta name="viewport" content="width=device-width,initial-scale=1">

    <%= favicon_link_tag "favicon.ico" %>
    <%= favicon_link_tag "favicon-32x32.png", rel: "icon", type: "image/png", sizes: "32x32" %>
    <%= favicon_link_tag "apple-touch-icon.png", rel: "apple-touch-icon", type: "image/png" %>
    <link rel="manifest" href="/site.webmanifest">

    <%= csrf_meta_tags %>
    <%= csp_meta_tag %>
    <%= stylesheet_link_tag "application", "data-turbo-track": "reload" %>
  </head>
  <body>
    <%= yield %>
  </body>
</html>

Pass type: and rel: for anything that is not a classic .ico. The helper defaults to rel=icon and type=image/x-icon, which is wrong for PNG and SVG.

Check the small end first

16px

32px

48px

96px

180px

Rendered at true pixel dimensions. A mark that survives 16px survives the tab; one that only reads at 180px will not.

Rails favicon FAQ

Propshaft or Sprockets: does the helper change?

favicon_link_tag is the same. Propshaft is the Rails 8 default and serves logical paths from app/assets without a Sprockets manifest. If you still run Sprockets, keep the files under app/assets/images and keep using the helper.

Why put a copy in public/ as well?

Some clients request /favicon.ico before they parse link tags. A small root copy covers that case. The layout helpers still own the full set that modern browsers and iOS actually use.

The icon did not update after deploy.

Confirm assets:precompile ran and the layout is using favicon_link_tag so the href changed with the digest. If you only replaced a file in public/ with the same name, browsers may keep the old cached icon until the URL changes or a private window is used.

Related platforms

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