Download of HaTTiP 1.3 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The actual developer of this software for Mac is Pilgrimage Software. According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software. HaTTiP for Mac is included in Developer Tools.
From the developer:
HaTTiP is an HTTP client for web services. The application is designed to help you create and save commonly-used HTTP web service requests. The program lets you create a library of scripts (currently supports Java script) that you can use to modify dynamically a request before it is submitted.
You may want to check out more Mac applications, such as iGooMap, Navicat for Oracle or Dragonfly, which might be similar to HaTTiP.