Application Programming Interface

InvoiceXpress Documentation


In order to authenticate a user through our API, an API key must be used. All API endpoints are available via HTTPS. HTTP access is denied. Each API key authenticates a user inside an account, and it’s composed by arbitrary characters.

This key must be passed on the query string in each HTTPS request to authenticate the user. Although all endpoints are accessed through HTTPS, please keep this token as secure as possible in order to avoid third party’s to access your InvoiceXpress data.

We strongly recommend you re-generate your API Key from time to time.



You can find your ACCOUNT_NAME and API_KEY here: https://www.app.invoicexpress.com/users/api

On POST and PUT requests do not forget to specify on the Header:

Content-Type: application/json; charset=utf-8