Can I update an empty image field in my Webflow collection item using the API? I am currently using Google App Script and have no issues updating text-based and boolean-based fields, but when it comes to the image field, I am unable to make any changes. The API response only includes the image field if the CMS item already has an image uploaded, resulting in an error message. I have tried using PUT and PATCH methods, but have had no success. Is there any way to update a blank image field directly from the API? Thank you for any assistance.

You're encountering a known limitation of the Webflow CMS API — it does not support directly uploading or updating image fields using a URL through the standard PUT or PATCH methods if the field is currently empty.

Here’s a breakdown of the issue and possible workaround:

1. Webflow CMS API Limitations for Image Fields

• The API can update an image field only if it already has an image, because the field key won't even appear in the CMS item object unless it’s populated.
• The Webflow API does not accept raw image URLs in the request body. The image must be hosted on Webflow’s CDN, which requires a proper upload process.
• There is no current API endpoint to upload a file and get a valid Webflow-hosted URL — it's a missing feature users often request.

2. Why Your PUT/PATCH Attempts Fail

• Since the image field is empty, it’s not returned in the API response, which complicates constructing a correct update payload.
• Trying to pass external image URLs in your update won't work because Webflow ignores or rejects URLs that are not already hosted on their CDN.

3. Workaround: Manual or Semi-Automated Upload

There is no fully automated way to upload an image to an empty image field via API as of now, but here are your options:

• Manually upload an initial placeholder image for each CMS item using the Webflow Designer. Once the image field exists (i.e., not empty), you can update the URL via API to another Webflow CDN URL.
• If you control the initial image upload source, consider:
• Uploading the image manually to Webflow Assets or via the Designer.
• Using a third-party service (e.g., uploading to Webflow via Zapier + Uploadcare/FileStack), then saving that hosted image URL.
• Using an intermediary CMS like Airtable with integrations that funnel uploads into Webflow via Webhooks or tools like Make.com or Zapier.

4. Alternative Integration Tools

If Webflow's native API is insufficient, consider using:

• Make.com (formerly Integromat): Supports conditional flows where you can upload files and update image fields.
• Zapier with Uploadcare or similar: Automate image uploads into your Webflow collection via accepted formats.

Summary

You cannot update an empty image field via the Webflow API directly unless the image is already hosted on Webflow’s CDN and the field is populated. To work around this, either pre-fill image fields manually or use third-party tools to manage hosted uploads and connect them to Webflow.