Changelog

The Custom Fonts API adds seven new OAuth v2 endpoints under /v2/sites/{site_id}/custom_fonts. Apps can now manage a site’s custom fonts programmatically — uploading, listing, updating, replacing, and deleting fonts without any manual steps in the Webflow Designer.

For information on using custom fonts in sites, see Custom fonts.

What’s new

• Upload a font to a site, with full variable font axis metadata
• List a site’s custom fonts with pagination
• Get a single custom font by ID
• Update font metadata (family name, weight, italic, font-display) without re-uploading the binary
• Replace a font’s binary while preserving the font’s ID and references
• Delete a custom font by ID
• Batch delete custom fonts in one request, with a per-font success and failure manifest

What you can build

Foundry and font-platform apps. Apps that license fonts can provision the licensed binaries straight into a customer’s Webflow site. Your user browses your library, selects a face, and the font appears in the site’s typography picker.

Brand-system and multi-site management apps. Agencies managing many sites under one workspace can keep the same brand fonts in sync across every site. Push a new corporate typeface to all client sites in one batch, or remove a deprecated weight from all of them just as easily.

AI and MCP agents. An AI assistant can now complete a site’s typography setup end-to-end — upload the brand’s custom font and it is immediately available across the site’s surfaces, with no manual handoff.

Authentication and scopes

The API reuses the existing sites:read and sites:write OAuth scopes. No new scopes are required, and existing app installations don’t need to re-authorize.

Upload handshake

Font uploads use the same presigned-S3 handshake as the Assets API.

1. POST to Webflow with the font metadata and the MD5 hash of the binary. Webflow returns 202 Accepted with a customFont object and a presigned upload object.
2. POST the binary directly to upload.url as multipart/form-data, including every key from upload.fields. The binary goes in a field named file, which must be the last field in the form. S3 returns 201 Created on success.

The font is immediately available in the site’s typography picker after the S3 upload completes.

Limitations

• Supported formats: WOFF2, WOFF, TTF, OTF, EOT. SVG fonts are not supported.
• File size: Uploads exceeding 4 MB are rejected by S3.
• Per-site limit: Each site has an internal cap on total custom fonts. Exceeding the cap returns 409 Conflict.
• Batch delete: Accepts 1-100 font IDs per request.

New endpoints