Zund Router: send a bundle once, reach 8 builders (free, ~2 ms response)

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Hi all, we run Zund, a small independent block builder.

We just opened the Zund Router: one endpoint that forwards your eth_sendBundle to Titan, Quasar, BuilderNet, Eureka, Beaver, bombora, the Flashbots relay and Zund in parallel.

How it works

  • Your request body and your X-Flashbots-Signature are forwarded unchanged, so each builder sees you, not us.
  • Response is immediate (~2 ms median); per-builder results are available via zund_routerStatus. Use ?wait=1 if you prefer to wait for all builders.
  • Warm keep-alive connections to every builder: overhead vs a warm direct send is ~0.5-1 ms; vs a cold direct send it is faster (cold Titan ~58 ms, cold Flashbots relay ~400 ms in our tests).
  • Bundles shaped like sandwiches are not forwarded.
  • Free, no API key, 30 req/s per IP.

Endpoint and docs: https://zundbuilder.com/router

Feedback and criticism welcome, especially latency numbers from your own location.