Is there any tool or software service offering only(primarily) mediation/fund handling services for the project milestone payments ? Like Upwork projects with guaranteed payments , where client has already submitted money with Upwork and freelancer will get it when the submitted work is approved. Is anyone doing it outside of upwork ? or is there any specific term used for this setup ? I feel this is useful, when I’m asking for advance payment from client before starting a project and client might feel reluctant to do so, specially incase of the first time collaboration. Having such system would keep both parties convinced.