routing.mode on the request. The default is smart.
fallback: true continues with the other vendors in smart order after the caller’s list. A pinned call still stops at the first conclusive verdict, and it continues when the verdict is not conclusive.
max_credits stops the plan before a step that would exceed the cap. It does not skip that step and keep going.
timeout_ms is optional. Omit it and each vendor uses its own timeout. Set it to a whole number of milliseconds, at least 1, and each vendor waits that long or its own timeout, whichever is shorter. When the time is up, that step is not charged, it is not counted for the hit rate or health, and the next vendor runs. Example: 3000.
For email.validate, conclusive verdicts are deliverable and undeliverable. catch_all and unknown are not conclusive, so smart, cheapest, and pinned continue.