JavaScript SDK: environment variables

Environment variables live on api.apps.envs. Every method takes the app id first and returns the app’s variables as a plain Record<string, string>. Examples use the api client from Creating the client. appId is the id of one of your apps: api.account.me() lists them.

Static apps have no environment variables: every method answers 400 STATIC_APP_ENV_NOT_SUPPORTED. A change takes effect on the next restart.

Reading the variables

const envs = await api.apps.envs.get(appId);

console.log(envs.NODE_ENV);

Adding or updating variables

envs.set(appId, envs) adds the given keys and overwrites the ones that already exist. Other variables are kept. It returns every variable after the change.

const envs = await api.apps.envs.set(appId, {
    NODE_ENV: "production",
    LOG_LEVEL: "info",
});

Replacing every variable

envs.replace(appId, envs) replaces all variables with the given set. Keys not in the object are removed.

await api.apps.envs.replace(appId, { NODE_ENV: "production" });

Removing variables

envs.delete(appId, keys) removes the given keys and returns the remaining variables.

const remaining = await api.apps.envs.delete(appId, ["LOG_LEVEL"]);

Limits and errors

Status	Code	When
400	`STATIC_APP_ENV_NOT_SUPPORTED`	The app is static
400	`INVALID_ENV_CONTENT`	The variables are not a valid object (or, for `delete`, an empty list)
400	`TOO_MANY_ENV_VARS`	The result would have more than 256 variables
400	`ENV_NAME_TOO_LONG`	A key is over 1024 characters
400	`ENV_CONTENT_TOO_LONG`	A value is over 4096 characters
400	`READ_FAILED`	The cluster could not read the variables

Next steps

Deploys

Deploy on every push, with a webhook or the GitHub App.

Environment variables API reference

The REST endpoints behind these methods.

Variables from the CLI

The same actions from the terminal.

Read variables in your code

Set variables from the dashboard, CLI or API and read them at runtime.

CLI

VS Code

SDKs

JavaScript SDK: environment variables

Reading the variables

Adding or updating variables

Replacing every variable

Removing variables

Limits and errors

Next steps

Deploys

Environment variables API reference

Variables from the CLI

Read variables in your code

​Reading the variables

​Adding or updating variables

​Replacing every variable

​Removing variables

​Limits and errors

​Next steps

Deploys

Environment variables API reference

Variables from the CLI

Read variables in your code

Reading the variables

Adding or updating variables

Replacing every variable

Removing variables

Limits and errors

Next steps