What determines Bridge Distribution method?

I noticed that my new bridge went from Bridge Distribution method None to Moat then after a while back to None again, according to its metrics page.

What determines Bridge Distribution method? Is it purely automated depending on certain criteria? Is there manual intervention? What causes the BridgeDistribution specified in torrc to either override or be overridden by other considerations?

How do I change my bridge distribution method?

BridgeDB implements four mechanisms to distribute bridges: HTTPS, Moat, Email, and Reserved. Bridge operators can check which mechanism their bridge is using, on the Relay Search. Enter the bridge’s <HASHED FINGERPRINT> in the form and click “Search”.

Operators can also choose which distribution method their bridge uses. To change the method, modify the BridgeDistribution setting in the torrc file to one of these: https, moat, email, none, any.

Bridge distribution mechanisms

BridgeDB implements four mechanisms to distribute bridges: “HTTPS”, “Moat”, “Email”, and “Reserved”. Bridges that are not distributed over BridgeDB use the pseudo-mechanism “None”. The following list briefly explains how these mechanisms work and our BridgeDB metrics visualize how popular each of the mechanisms is.


The “HTTPS” distribution mechanism hands out bridges over this website. To get bridges, go to bridges.torproject.org, select your preferred options, and solve the subsequent CAPTCHA.


The “Moat” distribution mechanism is part of Tor Browser, allowing users to request bridges from inside their Tor Browser settings. To get bridges, go to your Tor Browser’s Tor settings, click on “request a new bridge”, solve the subsequent CAPTCHA, and Tor Browser will automatically add your new bridges.


Users can request bridges from the “Email” distribution mechanism by sending an email to bridges@torproject.org and writing “get transport obfs4” in the email body.


BridgeDB maintains a small number of bridges that are not distributed automatically. Instead, we reserve these bridges for manual distribution and hand them out to NGOs and other organizations and individuals that need bridges. Bridges that are distributed over the “Reserved” mechanism may not see users for a long time. Note that the “Reserved” distribution mechanism is called “Unallocated” in bridge pool assignment files.


Bridges whose distribution mechanism is “None” are not distributed by BridgeDB. It is the bridge operator’s responsibility to distribute their bridges to users. Note that on Relay Search, a freshly set up bridge’s distribution mechanism says “None” for up to approximately one day. Be a bit patient, and it will then change to the bridge’s actual distribution mechanism.