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Environment variables

Multiple API checks can target the same server/service. In this case, your checks might need the same configuration item like an authentication token, a specific user name or even just some specific part of the URL. You can use global variables to ‘DRY’ up your checks and store these variables in just one place.

Managing variables

You can add variables on the Environment variables tab. The variables stored here are globally accessible throughout Checkly, hence the “Global environment variables” title*.

All variables are stored as string values. You can click the lock icon to encrypt the values and hide the value from all users that do not have write access.

adding variables

Accessing variables in API checks

Environment variables are exposed to your API checks using the common Handlebars/Moustache templating delimiters, i.e. {{BASIC_PWD}}. Variables can be used in the following API checks fields:

  • URL
  • Body
  • Header values
  • Query parameters values
  • Basic authentication username and password

When typing in most of the variable-enabled fields we show a small helper popup to help select the right variable.

access variables

Note, just the Body input field does not show this helper popup.

Using Handlebars helpers & built in variables

Next to your own variables, we’ve added some built-in variables and extended the Handlebars templating system:

helpers description
{{REGION}} Resolves to the AWS region name, i.e. us-east-1.
{{$UUID}} Generates a random UUID/v4, i.e. 9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d.
{{$RANDOM_NUMBER}} Generates a random decimal number between 0 and 1000, i.e. 345.
{{moment}} Generates a date or time using moment.js and allows for formatting:

  • {{moment "YYYY-MM-DD"}} generates a date, i.e. 2020-08-26
  • {{moment "2 days ago" "YYYY-MM-DD"}} generates the date two days ago: 2020-08-24
  • {{moment "last week" "X"}} generates a UNIX timestamp from last week: 1597924480

A practical example of using the {{moment}} helper would be setting the pagination options on a typical API endpoint:

 GET https://api.acme.com/events?from={{moment "last week" "X"}}&to={{moment "X"}}

You can find the full list of helpers in the README.md file of the underlying library we are using. For a full overview of date formatting option, check the moment.js docs.