Loading Python and pyrxd (about 12 MB the first time, cached after that)…
pyrxd builds and signs real Radiant transactions in this tab. A small Python "node" decides whether to accept each one, then mines a block. It checks:
It does not run Radiant's script interpreter. A script it does not recognise is accepted with a warning that its input was not evaluated. Timelocks are not enforced, and faucet coins can be spent at once. The real node is the authority on all of this: pip install pyrxd, then pyrxd regtest up gives you one on your own machine.
The keys are made by a pure-Python secp256k1 written for this page, because the C library pyrxd normally uses cannot run in a browser. It is checked against that library in pyrxd's tests, but it is not constant-time and must never hold a key that matters.