---
title: 'Environment Variables'
description: 'Environment Variables'
position: 3
category: 'Developer Resources'
fullscreen: true
menuTitle: 'Environment Variables'
---

| Variable                | Mandatory | Comments                                                                         | If absent                                  |
|-------------------------|-----------|----------------------------------------------------------------------------------|--------------------------------------------|
| NC_DB                   | Yes       | See our database URLs                                                            | A local SQLite will be created in root folder  |
| DATABASE_URL            | No        | JDBC URL Format. Can be used instead of NC_DB. Used in 1-Click Heroku deployment|   |
| DATABASE_URL_FILE       | No        | path to file containing JDBC URL Format. Can be used instead of NC_DB. Used in 1-Click Heroku deployment|   |
| NC_PUBLIC_URL           | Yes       | Used for sending Email invitations                   | Best guess from http request params        |
| NC_AUTH_JWT_SECRET      | Yes       | JWT secret used for auth and storing other secrets                               | A Random secret will be generated          |
| NC_SENTRY_DSN           | No        | For Sentry monitoring                                                     |   |
| NC_CONNECT_TO_EXTERNAL_DB_DISABLED | No | Disable Project creation with external database                              |   |
| NC_DISABLE_TELE | No | Disable telemetry                              |   |
| NC_BACKEND_URL | No | Custom Backend URL                              | ``http://localhost:8080`` will be used  |