Environment Config Reference

Environment Config Reference

The EnvironmentConfig object is used to configure services, volumes, and shared variables in Railway.

Structure

{
  "services": {
    "<serviceId>": {
      "source": { ... },
      "build": { ... },
      "deploy": { ... },
      "variables": { ... },
      "networking": { ... }
    }
  },
  "sharedVariables": { ... },
  "volumes": { ... },
  "buckets": { ... }
}

Only include fields being changed. The patch is merged with existing config.

Service Config

Source

Build

Deploy

Variables

Set to null to delete a variable.

For variable references, see variables.md.

Lifecycle

Multi-Region Config

Controls replica count per region. Structure: region name → { numReplicas } or null to remove.

{
  "multiRegionConfig": {
    "us-west2": { "numReplicas": 3 },
    "europe-west4-drams3a": { "numReplicas": 2 }
  }
}

Available Regions

Interpreting User Requests

• "add 3 replicas to europe" → { "europe-west4-drams3a": { "numReplicas": 3 } }
• "add a replica to all regions" → set numReplicas: 1 for all 4 regions
• "remove from asia" → { "asia-southeast1-eqsg3a": null }
• "increase replicas to 5" (no region specified) → query current config first, update existing region(s)

Important: When user doesn't specify a region, query the current multiRegionConfig and modify the existing region(s). Don't assume a default region.

Common Operations

Set Build Command

{ "services": { "<serviceId>": { "build": { "buildCommand": "npm run build" } } } }

Set Start Command

{ "services": { "<serviceId>": { "deploy": { "startCommand": "node server.js" } } } }

Set Replicas

{ "services": { "<serviceId>": { "deploy": { "multiRegionConfig": { "us-west2": { "numReplicas": 3 } } } } } }

Add Variables

{ "services": { "<serviceId>": { "variables": { "API_KEY": { "value": "xxx" } } } } }

Delete Variable

{ "services": { "<serviceId>": { "variables": { "OLD_VAR": null } } } }

Add Shared Variable

{ "sharedVariables": { "DATABASE_URL": { "value": "postgres://..." } } }

Change Docker Image

{ "services": { "<serviceId>": { "source": { "image": "nginx:latest" } } } }

Connect GitHub Repo

{ "services": { "<serviceId>": { "source": { "repo": "owner/repo", "branch": "main" } } } }

Change Git Branch

{ "services": { "<serviceId>": { "source": { "branch": "develop" } } } }

Set Health Check

{ "services": { "<serviceId>": { "deploy": { "healthcheckPath": "/health", "healthcheckTimeout": 30 } } } }

Change Builder

{ "services": { "<serviceId>": { "build": { "builder": "DOCKERFILE", "dockerfilePath": "./Dockerfile" } } } }

Delete Service

{ "services": { "<serviceId>": { "isDeleted": true } } }

Delete Volume

{ "volumes": { "<volumeId>": { "isDeleted": true } } }

New Service Instance

{ "services": { "<serviceId>": { "isCreated": true, "source": { "image": "nginx" } } } }

Note: isCreated: true is required for new service instances.