Notion API · api · fg-0556

Notion API returns validation_error for a custom_emoji icon that used to save and read back as null

If you see validation_error when setting a custom_emoji icon on a page, database, data source or callout, the cause and the fix for Notion API are below, last verified 2026-10-24.

Verified Oct 2026trust 50/100
Symptom
validation_error when setting a custom_emoji icon on a page, database, data source or callouticon saved earlier reads back as null
Cause
Since 2026-09-25, a custom_emoji icon must name a custom emoji that exists in the integration's workspace. Previously an invalid ID was saved and returned null.
Fix
Use a custom emoji ID from the same workspace as the integration, or use a standard emoji or native icon.
Apply
{"icon":{"type":"custom_emoji","custom_emoji":{"id":"<id_from_this_workspace>"}}}
Affected
Notion API page, database, data source and callout writes, from 2026-09-25
Sources

Last verified 2026-10-24 · Confirmed by 0 builders

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