HubSpot App Builder (Platform 2026.03)

This skill guides the development of full HubSpot apps on the latest developer platform (version 2026.03), covering project creation, configuration, UI extensions, serverless functions, agent tools, webhooks, and distribution.

Platform version 2026.03 was released on March 30, 2026 (GA confirmed in Spring 2026 Spotlight, April 14, 2026). It re-introduces full serverless function support for apps (including static-auth apps), introduces agent tools for Breeze Agents, expands App Homes into multi-page App Pages, and adds code sharing via npm workspaces. Previous version 2025.2 is now in "Supported" status.

Prerequisites

• HubSpot CLI v8.3.0+: npm install -g @hubspot/cli@latest
• Authenticate: hs account auth
• Node.js 22+ (minimum raised to v22 in 2025.2 and carried into 2026.03; was v20 in 2025.1)
• A HubSpot developer account
• Enterprise subscription required for production serverless functions (developer test accounts work without)

Project Setup Workflow

1. Create the Project