The Invoice API (Version 1.0) gives you access to pretty much all the features you can use on our dashboard and lets you extend them for use in your own application.
Before you do anything, you should create a free account that you can test the API against. We will provide you with test keys that you can use to make API calls.
We have language bindings in PHP and we highly recommend that developers use HTTP status codes to determine the result of an API call. Both request body data and response data are formatted as JSON.
Content type for responses will always be application/json.
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