title: holding payments with paypal like a credit card hold feature
body: <p>Dear stackoverflow members,</p>
  
  <p>I'm a developer who wants to implement an online payment service (this is my first time working on a custom payment service module) for one of our clients, and they have suggested to use PayPal.</p>
  
  <p>The scenario I have is like this:</p>
  
  <p>The website will offer users to create projects they need funding to complete, the project owner should specify how much funding he needs and the time needed to collect this fund:
  Example: "<strong>User-1</strong>" creates a new project Called "<strong>Project-1</strong>", he needs "<strong>$1000</strong>" to complete his project, and the time to collect this fund is "<strong>1 week</strong>".</p>
  
  <p>Now other users can help (support) this guy by donating money to his project in different amounts: "$1", "$10", "$100", etc ...</p>
  
  <p>What I need to implement using PayPal services is to hold the money from the "<strong>Supporters</strong>" in their accounts or any place, and after the "<strong>1 week</strong>" period has finished for collecting funds, the system will evaluate if the target budget has been reached or not, this means if "<strong>Project-1</strong>" fund raising reached "<strong>$1000</strong>" or not.</p>
  
  <p>If the fund was successful (it reached "<strong>$1000</strong>") the money will be deducted from the supporters (donators) accounts and sent to the project owner "<strong>User-1</strong>" (there will be fees for PayPal and the system), but if the fund was a failure, the money will not be deducted and the supporters (donators) will have there money back (remove the hold on this money).</p>
  
  <p>Is this something that can be done with PayPal services? or shall I investigate another approach? </p>
  
  <p>I tried and searched allot in PayPal documentations and many articles, but they all refer to direct payments and refunding operations, this will cost the system money since PayPal will deduct the fees on paying and refunding.</p>
  
  <p>I really appreciate any help on this matter.</p>
  
  <p>Best Regards</p>