jsschools

app.env

Reflects the current Node.js environment string (defaults to `NODE_ENV` or `"development"`).

Since Koa 2 Spec ↗

Syntax

app.env

Returns

string — The current environment name, e.g. `"development"`, `"production"`, or `"test"`.

Examples

import Koa from 'koa';

const app = new Koa();

app.use(async (ctx) => {
  ctx.body = { env: app.env };
});

app.listen(3000);
Output 
# NODE_ENV=production node server.js
{"env":"production"}

// Conditional behaviour based on env
if (app.env === 'development') {
  const { koaDevLogger } = await import('./dev-logger.js');
  app.use(koaDevLogger());
}
Output 
(logger only active in development)

Notes

`app.env` is read-only in practice; set `NODE_ENV` in the shell before starting your process. Koa uses it internally to decide whether to expose stack traces in error responses (only in non-production environments).

See also