Environment Variables

Environment variables let you pass configuration to your services without hardcoding values. They are available during both the build step and the runtime step, so your app can use them at compile time (e.g., NEXT_PUBLIC_* in Next.js) and at runtime.

How the agent sets variables

Your agent passes environment variables as key-value pairs in the env_vars parameter when calling create_service or update_service.

During service creation:

Tool Call

create_service(
  "name": "my-api",
  "repo": "ink/my-api",
  "env_vars": {
    "DATABASE_URL": "postgres://...",
    "API_KEY": "sk-...",
    "NODE_ENV": "production"
  }
)

Updating variables on an existing service:

Tool Call

update_service(
  "name": "my-api",
  "env_vars": {
    "DATABASE_URL": "postgres://new-host/...",
    "NEW_VAR": "value"
  }
)

When updating, the provided variables are merged with existing ones. The update triggers a redeployment so the new values take effect.

Available in build and run

Environment variables are injected into both stages of the deployment:

Stage	How they're used
Build	Available during `npm run build`, `go build`, etc. Use them for compile-time configuration like public API URLs or feature flags.
Run	Available to your running application process. Use them for secrets, database connections, and runtime config.

This means a variable like DATABASE_URL is accessible whether your ORM runs a migration during build or connects at runtime.

Framework prefixes

Some frontend frameworks only expose environment variables to client-side code if they use a specific prefix. Variables without the prefix are available server-side but won't be bundled into the browser build.

Framework	Required prefix	Example
Next.js	`NEXT_PUBLIC_`	`NEXT_PUBLIC_API_URL`
Vite (React, Vue, Svelte, etc.)	`VITE_`	`VITE_API_URL`
Create React App	`REACT_APP_`	`REACT_APP_API_URL`
Nuxt	`NUXT_PUBLIC_`	`NUXT_PUBLIC_API_URL`

Variables like DATABASE_URL or API_KEY that should stay server-side don't need a prefix — and shouldn't have one, to avoid leaking secrets into the client bundle.

Snapshots

Environment variables are snapshotted at deployment time. If you update variables via update_service, a new deployment is triggered automatically and the updated values take effect in the new build and runtime.

Common use cases

Database URLs — connection strings for your databases
API keys — third-party service credentials
Build-time config — public URLs, feature flags, NODE_ENV
Runtime config — port numbers, log levels, secrets

Security

Variables are stored encrypted at rest
Never logged or exposed in build output
Only accessible to the build and runtime environments of your service