Can Collection and Item IDs in Webflow change over time and cause 404 API responses even if the slugs still match?

Yes, Webflow Collection and Item IDs can change under certain conditions, potentially causing 404 API responses even when the slugs remain unchanged.

Here’s how and why this can happen when working with the Webflow CMS API:

1. When IDs Are Regenerated

• Collection and Item IDs are unique and system-generated.
• If you delete and recreate a Collection or duplicate a Collection, it will receive a new Collection ID—even if the slug stays the same.
• Similarly, deleting and recreating CMS Items will assign them new Item IDs.

2. Causes of 404 API Responses

• If your integration uses cached or hardcoded IDs, and the Collection or Item was deleted and rebuilt, Webflow will return a 404 Not Found error for the old ID.
• The slug might still appear valid in the Webflow UI or on the live site, but API requests rely on the internal ID, not the slug.

3. Best Practices to Avoid This

• Always fetch fresh IDs via the API using the slug if possible, rather than storing IDs permanently.
• Use the List Collection Items endpoint (GET /collections/:collection_id/items) to find the correct Item ID dynamically at runtime if your integration allows.
• Keep in mind that slugs are not unique across collections, so you must always reference the correct Collection ID with each item lookup.

4. How to Check for ID Changes

• In the Webflow CMS UI, there’s no direct way to see an item’s API ID.
• Use the CMS API to list items in a Collection and compare those IDs to what your integration is using.
• If an item has been deleted and rebuilt—even with the same slug—it will have a different ID.

Summary

Yes, Collection and Item IDs in Webflow can change, especially if items are deleted and recreated. API calls using outdated IDs will return 404 errors, regardless of the slug. Always fetch fresh IDs or dynamically look them up via the API to ensure consistency.