---
url: /custom-pages/client-side-functions.md
description: >-
  This section documents helpers and APIs that are available specifically to
  custom pages.
---

# Available Functions

This section documents helpers and APIs that are available specifically to custom pages.

## Available functions

* `ServerClient` - a lightweight fetch wrapper for calling server-side pages through `/serverside/execute`.
* `serverside` - legacy callback-based helper for evaluating a server-side page.

Use these pages when functionality is available in custom pages but not in standard server-side scripts.

## Recommended usage

* Use [ServerClient](/custom-pages/client-side-serverclient) for new work.
* Keep [serverside (Deprecated)](/custom-pages/client-side-serverside-legacy) only for maintaining older implementations.