HubSpot's Spring 2026 developer platform spotlight introduces date-based versioned APIs (starting with 2026-03) with 18-month support windows and twice-yearly breaking change cycles. New Service Keys (beta) replace legacy private apps, enabling admins to create self-service API access without full app development. Versioned developer documentation follows a YYYY-MM format. AI-assisted development is expanded via a remote HubSpot MCP Server (mcp.hubspot.com) and a local Developer MCP Server for building apps with natural language in editors like Cursor and Claude Code. Additional updates include HubSpot Projects v2026.03, serverless functions with UI extension support, app pages built with React, npm workspace code sharing for UI extensions, and Webhooks Journal API improvements.
