Paradigm’s leg pricing methodology attempts to take the quoted strategy prices as entered by the maker and calculate individual leg prices subject to the following broad constraints:
Calculate leg prices as close to the mark as possible
Leg prices must be in increments of minimum tick size
Leg prices must be within the Min and Max prescribed by the exchange for each leg
For options strategies, leg prices must preserve delta relationships:
Manual entry for individual leg prices when Paradigm is unable to calculate leg prices that are “sensical”
Currently, Paradigm does not allow zero or negative prices for the following strategies
Paradigm fees for Paradex products are free.
Log into your Paradex account
Go to Settings and click the Key Management tab
Select Trading Keys and click +Add New Key
Enter your Key Name and click Continue
Copy and save your Address, Private and Public Keys
On your Paradigm Dashboard, select Account tab under Derivatives (Listed) → Paradex
Click "+"
Enter a nickname for the Key. Input your Paradex API credentials (i.e. Address, Private Key) you just created
Click Add
You can add multiple Paradex API keys to your Paradigm Dashboard, then toggle between keys for trading/clearing in that selected Paradex (sub)account






Please see here