Tor and I2P mirrors
This site also runs as a Tor onion service and an I2P eepsite: the same pages, served directly over each network. No exit nodes touch the traffic, the mirrors keep no access logs, and they stay reachable from networks where tappony.app is blocked. The app itself never needs a server; these mirrors are just the website and its docs.
http://tapponymyz2tcisbwq7bnpq22yjxbxjc3nuqg2erzzuwfbzh6dm377id.onion/
http://i2nel66zdupkcxs7yj4cangfiaknfkfeoxzm4doglia36qsljf3q.b32.i2p/
An onion address is its own proof. A v3 onion address is the service's public key written out, so reaching it guarantees you reached this site and nobody in between. These are the only TapPony mirror addresses; anything else claiming to be TapPony on Tor or I2P is not.
First time?
Tor: install the Tor Browser and paste the .onion address into it.
I2P: install an I2P router, point your browser at its local HTTP proxy, then open the .b32.i2p address. The router takes a few minutes to find the network the first time.