Card #3240 · HubSpot App Marketplace
Confusion over HubSpot UI extensions serverless function API calls
Developers struggle to figure out how to use serverless functions to make API calls to external backends for custom cards. The implementation is highly dependent on the developer platform version, leading to confusion over which fetch method to use.
Pain score
0.48/ 1.00 · weighted product of four components
Reach0.50distinct authors (log-normalized)
Recency0.95freshness decay, half-life months
Engagement0.85upvotes + comments, normalized
Monetization0.25willingness-to-pay cues in evidence
§ Evidence — 2 verified quotes
The gotcha moment was figuring out how to use the serverless functions to make API calls to my backend and fetch the risks, plans data and show them on the respective Hubspot Company and Deal pages as custom cards.
Turns out it's highly dependent on the developer platform version, I migrated to latest version of the developer platform (2026.03) if you're on an older version there would be a completely different hubspot.fetch() method to use instead.
Comments are a Pro feature — join the conversation, share what you've shipped, hear what others are building.
Upgrade to Pro