For creating a race, you will need to use this API. You will have to contact us to get an API Secret for permission and access. There is information on https://test.runsignup.com/API/ProtectedAPI about using that secret to generate a signature. It also lets you generate a signature to be sure you have the right one.
Note that to prevent spam, you will receive an error if you try to create more than 10 new races from the same IP in 15 minutes. That might be an issue on initial imports of a large number of races, but if it is, contact us for a workaround.
The url_string field must be unique across all races on RunSignUp. It will be part of the race URL. For example, it is ScottCoffeeMoorestownRotary8KRace for https://runsignup.com/Race/NJ/Moorestown/ScottCoffeeMoorestownRotary8KRace.
Note that distance_units can be K for KM and M for miles. The dates here are in the race timezone.