---
title: "String interpolated environment variables"
description: ""
canonicalUrl: "https://zuplo.com/changelog/2023/04/21/string-interpolation-env-vars"
pageType: "changelog"
date: "2023-04-21"
tags: "runtime"
---
When using environment variables in with string interpolation in `routes.json`
or your OpenAPI file, i.e. `"option": "my-$env(ENV_VAR)-value"` `undefined`
environment variables would result in the string "undefined" (Javascript's
result of `${undefined}`). Instead undefined variables will now result in an
empty string.