Getting Started

Preview changes locally

View and share updates to your documentation

Fern offers two ways to preview changes to your documentation: a local development environment and unique preview links.

Local development

Fern allows you to view changes to your documentation in a locally-hosted environment.

Prerequisite: Please install Node.js (version 18 or higher) before proceeding.

Follow these steps to install and run the Fern CLI:

Step 1: Install the Fern CLI:

$npm i -g fern-api

Step 2: Navigate to the docs directory (where the fern folder is located) and execute the following command:

$fern docs dev

A local preview of your documentation will be available at http://localhost:3000. The functionality is available offline if you have run local development mode online at least once.

Some features (e.g. search) are disabled in the local development environment, including:

  • Search
  • SEO (favicon, auto-generated meta tags, etc.)
  • Authentication

Custom ports

By default, Fern uses port 3000. You can customize the port Fern runs on by using the --port flag. For example, to run Fern on port 3002, use this command:

$fern docs dev --port 3333

If you attempt to run Fern on a port that’s already in use, it will use the next available port:

Fern allows you to generate a shareable preview link displaying the current state of your docs. Each preview link is appended with a UUID and is not indexed. Currently, these links do not expire (this behavior is subject to change in the future).

Usage:

$fern generate --docs --preview

Example:

$fern generate --docs --preview
>
>[docs]: Found 0 errors and 1 warnings. Run fern check --warnings to print out the warnings.
>[docs]: Published docs to https://fern-preview-a1da0157-93ca-4b1f-b310-8dd34fb891ca.docs.buildwithfern.com
>┌─
>│ ✓  docs.example.com
>└─