To get an API key, first sign up for a Mathpix account. Once you have verified your email and logged in, you will need to create an OCR API Organization. Click on the OCR API Organizations tab:

Next, choose Create OCR API at the top right of your screen:

You will be required to add a credit or debit card in order to activate an API key. You will also be charged a one-time, non-refundable setup fee to enable your API keys.

Once you have created your OCR API organization, added your billing information, and paid your setup fee, you will see an API key on your dashboard that is ready to use. If you need additional API keys, you can create them by clicking Create Key:

You can access all the API request and reponse data from your API keys under the Results tab of your OCR API Organization settings:

You can check your total usage anytime under the Usage tab of your OCR API Organization settings:

You can also query hour by hour API usage using the following endpoint: https://docs.mathpix.com/#query-ocr-usage