Olx and Quicker both are a mediator between two persons want to sell or buy.But Olx is making it very simple to use and in security it is hiding you mobile number also and like all other messaging services it also gives user to response easily to messages.And it makes direct contact between buyer and seller .The only thing is that you should search your locality and you have to go for verifying and buying the product.But same time talking about quicker it also giving good service but it making complex to use by user and rather than locality it showing all products and quicker want to give serive like amaozon or flipkart. it gives service of pickup the product and the payment is made to quicker and then quicker makes payment to seller. but all user doesn’t like it. because it takes more time to buy anything.but it trying provide a secure connection between buyer and seller.but making overall comparison Olx is easy and simple to use But quicker is complex but more safe giving verified product but on olx you have to verify your product before buying.