The Public Test Grid

This page is about the "Public Test Grid", which is also called the "pubgrid". The pubgrid has several purposes:

  • to make it easier for people new to Tahoe-LAFS to begin to experiment
  • to enable small-scale trial use of Tahoe-LAFS
  • to help the Tahoe-LAFS community gain experience with grids of heterogeneous servers without a pre-existing social organization

The pubgrid also has two critical non-goals:

  • The pubgrid is not intended to provide large-scale storage, and it is not intended to be reliable. Don't store any data in the pubgrid if losing it would cause trouble.
  • Don't view the pubgrid as a free hundreds-of-MB backup service.

How To Connect To The Public Test Grid

The test grid is subject to being updated at random times, so compatibility is likely to break without notice. Also note that an upgrade could require all files and directories to be flushed, especially as storage formats change.

The introducer fURL for the testgrid is pb://

Social Norms

By running a client node you can store data in the pubgrid. The storage is provided by people who run storage nodes. They share disk space and network capacity as a courtesy to the Tahoe community in order to help newcomers and promote experimentation.

Norms for the pubgrid are similar to those for some private grids:

  • If you are just trying out tahoe and not contributing a server, only store a small amount of data, perhaps 1-20 MB. This is perfectly fine; people contribute resources so that new people can experiment.
  • If you are a more serious pubgrid participant, contribute some amount of disk space and run stable servers with public IP addresses (so that clients can connect to them). Then, only store about half as much in shares (3.3x expansion for 3/10 encoding) as you provide in storage.
  • People storing more than the above small amounts of data, as well as those running servers should be on the tahoe-dev mailing list.

Suggested server setup:

  • Enable expiration with 1-month lease maximums on your node, to keep it from just filling up.


The status of the pubgrid can be checked by either looking at your nodes status page. The community would welcome the contribution of a monitoring system for the grid.


The canonical way to access Tahoe-LAFS grids is to run your own client node. Having one's own node is necessary for the data that should remain private (plaintext, capabilities) to remain on your computers, while storage nodes provide storage of ciphertext.

Contact Info

If the pubgrid introducer appears to be down then either send an email to the tahoe-dev mailing list or get in touch on irc:// Note that because storage servers are contributed by the community it will probably be true that not all advertised storage servers are always available. Only the operators of those storage servers will have the ability to address such situations.

Last modified at 2021-10-05T13:14:38Z Last modified on 2021-10-05T13:14:38Z