# Maxio Advanced Billing > Maxio Advanced Billing (formerly Chargify) provides an HTTP-based API that conforms to the principles of REST. One of the many reasons to use Advanced Billing is the immense feature set and [client libraries](page:development-tools/client-libraries). The Maxio API returns JSON responses as the primary and recommended format, but XML is also provided as a backwards compatible option for merchants who require it. ## Steps to make your first Maxio Advanced Billing API call 1. [Sign-up](https://app.chargify.com/signup/maxio-billing-sandbox) or [log-in](https://app.chargify.com/login.html) to your [test site](https://maxio.zendesk.com/hc/en-us/articles/24250712113165-Testing-Overview) account. 2. [Setup authentication](https://maxio.zendesk.com/hc/en-us/articles/24294819360525-API-Keys) credentials. 3. [Submit an API request and verify the response](page:development-tools/client-libraries#make-your-first-maxio-advanced-billing-api-request). 5. Test the Advanced Billing [integrations](https://www.maxio.com/integrations). Next, you can explore [authentication methods](page:introduction/authentication), [basic concepts](page:introduction/basic-concepts/connected-sites) for interacting with Advanced Billing via the API, and the entire set of [application-based documentation](https://docs.maxio.com/hc/en-us) to aid in your discovery of the product. ### Request Example The following example uses the curl command-line tool to make an API request. **Request** curl -u :x -H Accept:application/json -H Content-Type:application/json https://acme.chargify.com/subscriptions.json Authentication - Basic Authentication ## Docs - [Overview](https://developers.maxio.com/http/getting-started/overview) : Landing Page