Get all fields present on leads

Hey there,
I was trying to get all fields that are present on “leads”. For “deals” we have “dealFields” to get all fields present on “deals”.
How one can get all fields present on “leads”?
Also what is relation between between “leads” & “deals”, when compared schemas?

I couldn’t find an API to fetch lead fields as well. So hard coded at the moment based on the available fields

// URL for creating a deal
$url = 'https://' . $company_domain . '' . $api_token;

// URL for creating a lead
https://{COMPANYDOMAIN}**leads**?api_token=' . $api_token;

I can create a lead with a just a Title value
but cannot find out how to insert values into a custom field in the same Lead.

i can see that leads use the same custom values as deals, but does this mean to insert a custom value into a lead you need to add it as via the deals end point

https://{COMPANYDOMAIN} and pass the Lead ID with auth_token to it ?