Waterfall Routing

Waterfall routing implements a strict priority ordering: Buyer A > Buyer B > Buyer C. Every incoming call tries Buyer A first. If Buyer A answers, the call succeeds. If Buyer A doesn't answer within a timeout (e.g., 5 seconds), the call automatically transfers to Buyer B. If B doesn't answer, it transfers to C. This waterfall continues until someone answers or all buyers are exhausted.

Waterfall is ideal for:

**Buyer hierarchies**: You have a preferred buyer (primary agent, law firm) who should get first priority, a secondary buyer (backup agent) for overflow, and a tertiary buyer (competitor or outsource team) for final fallback.

**Availability-based routing**: If your primary buyer is frequently unavailable (appointments, breaks), waterfall ensures calls reach backup buyers instead of going to voicemail.

**Cost optimization**: If Buyer A charges $30/call and Buyer B charges $20/call, you want to maximize A's calls (who's likely higher quality). Waterfall does this: A gets first shot, only overflow goes to B.

**Geographic expansion**: You might prefer local buyers (Buyer A in CA) for CA calls, but if none are available, fall back to a regional buyer (Buyer B across West Coast).

Waterfall requires careful parameter configuration:

**Answer timeout**: How long does the platform wait for Buyer A to answer before advancing? Too short (2 sec) and A might miss calls. Too long (10 sec) and callers get frustrated.

**Ring no-answer threshold**: How many ring cycles before advancing? Some implementations wait 4 rings, some wait until voicemail picks up.

Waterfall doesn't optimize for price (unlike auction). It optimizes for hierarchy. If Buyer A bids $10 and Buyer B bids $40, waterfall still sends all calls to A first.

Waterfall is not ideal when you want to maximize revenue (use auction) or distribute fairly (use round-robin). But when you have clear buyer hierarchies and want deterministic fallback behavior, waterfall is the right choice.