# Variables reference

> The variables 5050cloud provides to every replica, their Railway aliases, the reference syntax and the variables that change settings.

The variables 5050cloud provides to every replica, their Railway aliases, the reference syntax and the variables that change settings.

## Provided variables

| Variable | Value |
|---|---|
| `PORT` | The target port (default 8080) |
| `FIFTY_PUBLIC_DOMAIN` | The service's first public domain |
| `FIFTY_PRIVATE_DOMAIN` | `<name>.internal` |
| `FIFTY_PROJECT_ID`, `FIFTY_PROJECT_NAME` | The project |
| `FIFTY_ENVIRONMENT_ID`, `FIFTY_ENVIRONMENT_NAME` | The environment |
| `FIFTY_SERVICE_ID`, `FIFTY_SERVICE_NAME` | The service |
| `FIFTY_DEPLOYMENT_ID` | The deployment |
| `FIFTY_SNAPSHOT_ID` | The deployment id, used as a build snapshot id |
| `FIFTY_REPLICA_ID` | This replica |
| `FIFTY_REPLICA_REGION`, `FIFTY_HOST` | The host this replica runs on |
| `FIFTY_PROCESSES` | Processes per replica |
| `FIFTY_GIT_COMMIT_SHA`, `FIFTY_GIT_BRANCH`, `FIFTY_GIT_REPO_OWNER`, `FIFTY_GIT_REPO_NAME`, `FIFTY_GIT_COMMIT_MESSAGE`, `FIFTY_GIT_AUTHOR` | The commit, for GitHub sources |
| `FIFTY_VOLUME_NAME`, `FIFTY_VOLUME_MOUNT_PATH` | The volume, when there is one |
| `FIFTY_TCP_PROXY_DOMAIN`, `FIFTY_TCP_PROXY_PORT`, `FIFTY_TCP_APPLICATION_PORT` | The TCP proxy, when there is one |

With **Railway aliases** on (the default), the same set is also provided as `RAILWAY_*` (for example `RAILWAY_PUBLIC_DOMAIN`), plus `RAILWAY_ENVIRONMENT` with the environment name. Your own variables win over provided ones.

## Not provided

Railway's `OTEL_*` tracing variables. To send traces to your own collector, set `OTEL_EXPORTER_OTLP_ENDPOINT` and the related variables yourself, for example as shared variables.

## Reference syntax

| Syntax | Meaning |
|---|---|
| `${{NAME}}` | Same service |
| `${{shared.NAME}}` | Shared variable of the environment |
| `${{Service Name.NAME}}` | Another service in the environment, by name (case-sensitive, spaces allowed) |

Resolution is recursive (up to 10 levels) with cycle detection. Unknown targets resolve to an empty string with a warning.

## Template functions

| Function | Result |
|---|---|
| `${{secret(len)}}` | Random string of `len` characters from `A-Za-z0-9` |
| `${{secret(len, "alphabet")}}` | Random string from the given characters |
| `${{randomInt(min, max)}}` | Random integer |

They are evaluated once, when the value is first saved.

## Variables that change settings

When the matching setting is empty, these override it: `RAILWAY_DOCKERFILE_PATH`, `RAILWAY_RUN_UID`, `RAILWAY_SHM_SIZE_BYTES`, `RAILWAY_HEALTHCHECK_TIMEOUT_SEC`, `RAILWAY_DEPLOYMENT_OVERLAP_SECONDS`, `RAILWAY_DEPLOYMENT_DRAINING_SECONDS`, `NO_CACHE`, `RAILPACK_*` and `NIXPACKS_*` build hints, and the `FIFTY_` equivalents.

## Masking

Values of variables whose names contain `SECRET`, `TOKEN`, `PASSWORD`, `PASSWD`, `PASS`, `KEY`, `PRIVATE`, `CREDENTIAL`, `DSN` or `AUTH`, sealed variables, and passwords inside URL values are replaced by dots in build and deploy logs when they are at least 6 characters long.