Sighten has three public environments: engine.sighten.io, mirror.sighten.io, and onboard.sighten.io.
Engine is the production website. All live jobs should be created here. It's the only server that can run credit and generate legally binding documents. No test job should be run in this environment.
Mirror is a direct copy of Engine. At approximately 12:00 am pst, Mirror is erased and reset with a copy of the jobs on Engine. Mirror is the best server for testing, although jobs will only remain in the environment for at most 24 hours. Here, you cannot run credit or generate legally binding documents.
Onboard is another test environment that is also used for onboarding new customers. Engine jobs are copied down to Onboard with every release, and is thus reset on a two week cadence. Onboard is useful for testing, although the operational functionality may not be identical to Engine. You cannot run credit or generate legally binding documents on Onboard.