Bitcoin Forum

Hi, I'm finding out, I hope someone can help me. What kind of wallet do the lending platforms use? one generates a deposit address, for example Hextracoin, but one does not have the private key. Do they use block.io, or one like Electrum? some other that generates many directions for each client? I hope your help please.

Most services claim that majority of their funds are stored in a cold storage but we can't really verify if it's true. When you deposited your money on these third party services,
you are trusting them with your funds so in short it's all about "trusting" that what they claim is true. Meaning to say, its impossible to know what kind of wallet they are using unless you've seen them for yourself but they can just claim whatever they want.

And every address has a corresponding private key, it's just that some services don't give their users an access to these.

We cannot able to identify what wallet they are using, if you think they are using non private key contained wallet they should use amu online open wallet like coinbase and etc. To maintain secure stream of payment they will be sticks with the cold storage or desktop wallet with the multiple seeds. If you know support email id of btcjam the you chdcl with them
 They are one of the long run lending platform.

What lending platform do you mean? The only lending opportunities, I know, are margin-lending on Poloniex und Bitfinex and here at Bitcointalkforum. By preposter recommended lending platform BTCjam is closing /disabled any new lending.
https://blog.btcjam.com/2017/05/25/btcjam-is-closing/

Be careful with so called "lending platforms", most of them are scam. Better ask here in forum, whether the service, you want to use, is legit.