Sandbox network for fediverse developers

I’m talking to a new ActivityPub server library that’s releasing its first alpha soon, and they’ve set up a hosted sandbox for testing. Naturally, this test instance will be unfederated because it’s just meant for demo purposes.

It did get me thinking though: Is there no sandbox version of the fediverse network out there? A kind of emulation of the real ActivityPub network, made of bot accounts, to which developers can federate their apps for testing.

Related: The ActivityPub test suite

Not that I know of, but it would be a great addition to the recently started fediverse-ideas.

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I would be very cautious when implementing something like this. In particular, if features are made available that one wouldn’t expect in production.

Call the above a hunch based on what happened with Mastinator by @boyter.

My understanding is that Mastinator was federated with real servers and proxied real user accounts instead of creating purely artificial bot accounts to simulate actors.

Transcript: Interview with Boyter about Mastinator ⋅ Plume (

Explore the fediverse, but use block like it’s a machine gun in a zombie apocalypse | Ben E. C. Boyter

What I meant to express by “a hunch based on what” is that I don’t know what the actual threat scenarios are. However, I suspect that there are several non-trivial ones. So one shouldn’t launch such a “sandbox network” on the internet without doing a careful analysis. Such an analysis can only occur once one has a firm concept of the sandbox to use.

So whoever works on this idea: be careful.