Use Fiddler to capture API requests and responses

• Fiddler is a debugging proxy. When running, it listens for HTTP requests on port 8888. If capturing is enabled, Fiddler changes the system proxy settings to route all requests through Fiddler. For example, all modern browsers will send requests through Fiddler if capturing is enabled, and so will all API clients that respect the system proxy settings. It is also possible to change an API client to explicitly use localhost:8888 as a proxy for sending requests.
• Fiddler sessions (comprising a request + response pair) can be saved to a file format with the extension .SAZ, which can in turn be added you your support ticket with Fotoware. We prefer receiving this format rather than cut-and-pasted individual requests, as it allows us to analyze requests and responses in Fiddler and prevents data from being corrupted by e.g. an email server or client.
  Even "heavy" requests (such as upload and download) can be easily debugged in this format, since attached files can be exported.
• Failed requests should generate warnings in the FotoWeb server logs also, especially for responses with status codes below 500 (internal server error). These should also be included along with any failed request logs.

You can download Fiddler from the Telerik website (external site).