| `DATABASE_URL` | string | The database URL; is of the form: `postgresql://localhost/blog_development`. |
| `ENABLE_BOOTSNAP` | string | Enables Bootsnap for speeding up initial Rails boot (`1` to enable). |
| `ENABLE_BOOTSNAP` | string | Toggles [Bootsnap](https://github.com/Shopify/bootsnap) for speeding up initial Rails boot. Enabled by default for non-production environments. Set to `0` to disable. |
| `EXTERNAL_URL` | string | Specify the external URL at the [time of installation](https://docs.gitlab.com/omnibus/settings/configuration.html#specifying-the-external-url-at-the-time-of-installation). |
| `EXTERNAL_VALIDATION_SERVICE_TIMEOUT` | integer | Timeout, in seconds, for an [external CI/CD pipeline validation service](external_pipeline_validation.md). Default is `5`. |
| `EXTERNAL_VALIDATION_SERVICE_URL` | string | URL to an [external CI/CD pipeline validation service](external_pipeline_validation.md). |