To configure your Qortal Core settings, you can open and edit the settings.json file using any text editor. Changes are only applied when loading the Core, so it must be restarted to take effect. This file is found in the main "qortal" folder created when installing the Core. On Windows however, it would be in the "%localappdata%/Qortal" folder by default. Note: There is also a settings.json file in "C:/Program Files/Qortal". Changing that copy of the file is recommended for advanced users only, as it is just meant to specify the "userPath" setting, which tells the Core where to find your primary settings file, and database folder. Info on relocating the database folder is given below.

The settings file is written using the standard JSON format. This requires a curly brace at the start and end, and each setting "key" should be enclosed in quotes, followed by a colon, then the setting "value" which also needs quotes if it's a text value. Numerical or boolean (true/false) values do not need quotes. A comma must be placed between each key/value pair, but not after the last entry. JSON is whitespace neutral, so any spaces, tabs, or new lines are ignored and not required. Here is an example showing two equivalent layouts:

{
    "setting1": "enabled",
    "setting2": true
}

{"setting1":"enabled","setting2":true}

The full list of user-customizable settings (and their default values) can be found at the following link: https://github.com/Qortal/qortal/blob/master/src/main/java/org/qortal/settings/Settings.java

Here is explanation of the most commonly used settings:

bindAddress - Adding "bindAddress":"0.0.0.0" will force IPv4 (disabling IPv6).

apiDocumentationEnabled - Setting this to true will enable the API Documentation page, found at http://localhost:12391/api-documentation by default. This page assists in using the API, also providing information and examples for available API calls.

autoUpdateEnabled - Setting this to false will disable the Core from automatically updating when a new version is released and approved.

repositoryMaintenanceMinInterval & repositoryMaintenanceMaxInterval - These settings determine the timeframe in which the database will be automatically "trimmed" to reduce storage space used. The value should be given in milliseconds. For example, 259200000 is the default minimum, which equals 3 days. Note: A random value between these two options is chosen when starting the Core. That means if you restart the Core daily, no maintenance will occur (unless your settings allow for values lower than one day).

topOnly - Setting this to true will enable "top only sync" which results in a much smaller database, however it will prevent the ability to look up data from older blocks. This can affect retrieving full information on older transactions, but will not interfere with most other features, like displaying your current balance. Note: Enabling this with a "full sync" database in place will cause the Core to convert it to "top sync". Disabling this with a "top sync" database will cause the Core to discard the database and download a "full sync" bootstrap, or sync from 0 if that is disabled. (See the following setting.)

bootstrap - Setting this to false will prevent the Core from automatically downloading the bootstrap file when no database is found. This would allow syncing blocks from peers, starting at 0 (the genesis block).