Mock leads generation using post

HI Guys
I am new here and still trying to get all the potential of postman.

At the moment I am using postman to mock a lead generation and check that my ‘Integromat’ works properly.

I basically create leads online (with landing pages) and send them to the final client (who can be a gaming site, financial products, streaming, dating ecc ecc) using Integromat to check, fw, and store them.

at the moment I am filling test leads next to the keys I created and send them to my webhook waiting for a response.

I was wondering if I can use postman to upload a bulk list of leads (I have them in csv but can transform them in json) and send them to the webhook but once at the time…I tried the bulk upload but it basically send them as a whole and the client’s server doesn’t accept them

any hint?

thank you