2026.03, apps built on the developer platform fully support and deploy serverless functions. These server-side JavaScript functions execute within HubSpot’s infrastructure, which eliminates the need to manage your own external server while still providing enhancements over older versions of the platform (e.g., 2025.1).
Comparison of serverless function options
2026.03 serverless functions are best suited if you want to work with UI extensions and leverage HubSpot’s REST APIs, while CMS serverless functions are better used in tandem with your CMS website. The table below provides more details on the advantages offered both serverless function options:| Feature | 2026.03 serverless functions | CMS serverless functions |
|---|---|---|
| Private functions | ✅ Yes | ❌ No |
| Public endpoints | ✅ Yes (Content Hub Enterprise only) | ✅ Yes |
| UI extension support | ✅ Yes | ❌ No |
| Test account support | ✅ Yes | ❌ No |
| NPM packages | ✅ Yes | ✅ Yes |
Get started
To get started with serverless functions for 2026.03 apps, check out the articles below:- Check out the serverless functions guide for a walkthrough of how to create a new app that includes an app card wired up to an example serverless function.
- Consult the serverless function reference article for information on project structure, schema details, limits, and more.