What does the Gmail reputation graph actually mean?

Gmail Postmaster Tools displays domain reputation using four levels:

High indicates Gmail trusts your domain. Mail should reach the inbox reliably for engaged recipients.

Medium means Gmail has some concerns. You may experience occasional spam folder placement or throttling.

Low signals significant trust issues. Expect frequent spam folder placement and potential delivery delays.

Bad indicates severe reputation damage. Most mail will likely go to spam, and you may face delivery failures.

The graph shows reputation over time, helping you correlate reputation changes with specific campaigns or events.

The reputation graph is your port authority clearance level. High clearance means expedited docking. Bad clearance means quarantine and thorough inspection of every shipment.