prop() references in formula property writes
By Steven Van ·
Formula expressions submitted through Update a data source now store prop("Property Name") references exactly as written.
Notion announced prop() references in formula property writes on August 12, 2026.
What changed
Formula expressions submitted through Update a data source now store prop("Property Name") references exactly as written. Previously, the API accepted some expressions but silently rewrote them — most visibly, a reference to a unique ID property dropped the ID's prefix from computed values, and a prop() reference inside an array literal emptied the array. Expressions the API can't store now return a validation_error instead. Formulas saved before this fix keep their old stored expression until you resubmit the update. Formula properties created through the API also now keep their result type, so number formatting options stay available in Notion and other formulas can reference them with prop().
