Live · real WASM · real threads

Five nodes, five workers, one log

Each node below is a separate WebAssembly instance running in its own Web Worker, ticking on its own timer. Nothing here is scripted: the leader is whichever node's election clock fires first, and the message order is whatever the threads produce. Break things and watch Raft hold the line.

Log

Network

Failure

Speed

Packet loss 0%

Delay none

Leader Follower Candidate Crashed

Vote Append / entries Heartbeat Response

Safety invariants · checked every frame

Election Safety holds ≤ one leader per term

State-Machine Safety holds committed prefixes agree

leader(s): -

connectednetwork

0elections

0in flight

0msgs sent

0dropped

Replicated log · term colour per entry, filled = committed

Event log

Honest boundary. The nodes are truly concurrent and their message interleaving is non-deterministic - but they share one machine and one browser, and the "network" is postMessage between threads, not TCP between hosts. This is not a distributed deployment; it is a faithful concurrency model of one. A crashed node loses its in-memory state and catches up from the leader on restart.