Two ways to buy calls
If you buy inbound phone calls at scale, you have two procurement models: real-time bidding (RTB) through an exchange, or direct deals negotiated with individual publishers.
Both work. Both have been around for years. But they produce very different economics, and most buyers default to one model without fully understanding the trade-offs. This article breaks down the comparison across five dimensions that matter most to demand-side call buyers: pricing transparency, quality control, scale, optimization speed, and attribution.
Pricing transparency
RTB: Price set per call
In an RTB auction, every call is priced on its own. Buyers bid on each call as it arrives, and the price moves with demand: by geo, source, time of day and how much buyers want that call right now.
Auctions come in two main forms. In a second-price auction, the winner pays just above the next-highest bid. In a first-price auction, the winner pays its own bid. TapQuality runs blind first-price auctions: you never see other buyers' bids, and you always know exactly what you pay, because it's what you bid.
The point is that you choose the price of every call, and you can change it in seconds. With target CPA bidding, the bid follows your own conversion data instead of a number fixed in a contract.
Direct deals: Negotiated rates
Direct publisher deals use fixed pricing -- a negotiated CPL (cost per lead) or per-call rate that stays constant for the duration of the contract. Common structures include flat per-call pricing (e.g., $28/call regardless of quality), tiered pricing based on call duration or disposition, and monthly minimums with volume discounts.
The advantage is predictability. You know exactly what you'll pay. The disadvantage is opacity. You have no idea whether you're paying market rate or 40% above it. The publisher knows their costs and margins. You don't.
Direct deals also create adverse selection risk. If you negotiate a $28 flat rate and the publisher's average cost to generate a call drops to $12, they have no incentive to pass savings along. Conversely, if their costs rise, they'll push to renegotiate or start sending lower-quality traffic.
Verdict: RTB wins on control. You set the price of every call, and you can change it as fast as your data changes.
Quality control
RTB: Checks before the bid
A good RTB platform checks each call before you commit budget. On TapQuality, every ping runs through:
- Block and do-not-call lists. Known bad numbers never reach your bid.
- Duplicate checks. A caller who already reached you from the same source in the last 30 days doesn't bill again.
- Reping checks. Callers sent by more than one partner in the last 24 hours are flagged.
- Your rules. Geo, schedule, source contract, caps.
- Your floor. For EnrollHere queues, live agent availability is checked before the bid, so you don't win calls nobody can answer.
With target CPA bidding, the bid itself reflects quality: your target, times the predicted conversion rate, times the quality of the source. As your sales data comes back, those rates update for your business, not the market average.
Direct deals: Manual QA and trust
With direct publishers, quality control is reactive. You buy calls, listen to recordings, flag bad ones, and request credits. Each dispute takes days, and there's always friction over what counts as a "bad" call.
Some publishers offer basic quality filters -- minimum call duration, caller ZIP code restrictions, IVR pre-screening. But these are blunt instruments compared to checking every call against your own conversion data. A 90-second call from the right ZIP code can still be completely unqualified.
The core problem is information asymmetry. Publishers have data about their traffic sources that they don't share with buyers. When quality drops, you find out after the money is spent. Pay-per-call's lemons problem explains why that gap can push good sources out of a market.
Verdict: RTB wins on quality control. Checks before the bid prevent bad spend rather than recouping it after the fact.
Scale
RTB: Exchange volume
RTB exchanges aggregate supply from hundreds of publishers, traffic sources, and networks. You reach that whole pool through one integration.
Need to scale from 200 calls/day to 2,000? Raise your bids and budgets. The exchange handles sourcing. You don't need to find, vet, and contract with new publishers individually.
Geographic expansion is equally simple. If you're buying Medicare calls in Florida and want to add Texas, you create a new campaign targeting TX ZIP codes. The exchange already has Texas supply from dozens of publishers.
The trade-off is that exchange volume fluctuates. Seasonal verticals like Medicare AEP see massive supply spikes in Q4 and drops in Q1. You're competing with other buyers for the same pool, so costs rise when demand is high.
Direct deals: Publisher caps
Direct publisher deals have hard volume caps. A publisher generating 100 Medicare calls per day in Florida can't suddenly deliver 500 because you increased your budget. Publisher volume is bounded by their traffic generation capacity -- their ad spend, their SEO rankings, their call center infrastructure.
Scaling through direct deals means adding more publishers. Each new publisher requires discovery, vetting, test campaigns, contract negotiation, and ongoing management. Adding 10 new publishers might take 2-3 months and significant account management overhead.
The upside of direct deals is supply exclusivity. If you have an exclusive agreement with a high-quality publisher, competitors can't bid on those calls. This matters in competitive verticals where the best publishers are capacity-constrained.
Verdict: RTB wins for scale and speed-to-volume. Direct deals win for exclusive access to specific high-quality sources, but can't match RTB for rapid scaling.
Optimization speed
RTB: Changes in minutes
On an RTB platform, a bid change takes effect on the next call. On TapQuality, campaign changes reach the bidder within 30 seconds, and dayparts run in 15-minute blocks, so you can react to the day while it is still happening.
AI can speed up finding what to change. TapQuality's optimizer proposes bid modifier experiments, for example a +25% geo modifier for Florida when Florida calls convert above average. Locked rules score each proposal against your target CPA, and you approve or dismiss it.
This means your campaigns can react to intraday shifts: a surge of good callers from one source, a drop in conversion rates during one daypart, a new buyer competing for the same calls.
Direct deals: Weekly reviews
With direct publishers, optimization is a manual process. The typical cadence: pull a weekly report, analyze conversion rates by publisher, identify underperformers, email the account manager requesting adjustments or credits, wait for a response, implement changes.
This cycle takes a week or more. During that time, you're still paying the same rate for traffic that may have degraded. If a publisher's traffic source changes mid-week -- they shift ad spend from Google to a lower-quality network -- you won't catch it until the next review cycle.
Even with dedicated account management, the feedback loop is fundamentally slower. Humans reviewing data weekly can't compete with algorithms testing continuously.
Verdict: RTB wins decisively. Changes that take effect on the next call beat a weekly review cycle.
Attribution
RTB: Ring pools and full-funnel tracking
RTB platforms integrate with ring pool technology to capture click-level attribution. Here's the flow:
- A visitor clicks a Google Ad and lands on your page. The ring pool assigns a unique tracking number and captures the gclid.
- The visitor calls the tracking number. The call enters the RTB auction.
- You win the auction. The call is routed to your agents.
- The call converts to a sale.
- You report the conversion back to the platform.
- TapQuality uploads the sale, tied to the original click, to Google Ads as an offline conversion. (Or sends it to your own systems by webhook, if you run the upload yourself.)
Google now knows that this specific keyword, in this specific ad group, drove a sale worth $X. Smart Bidding uses this signal to optimize future ad delivery. Meta and Microsoft Ads accept offline conversions in a similar way.
This creates a true closed loop: ad click, call, sale, and postback all connected through a single attribution chain.
Direct deals: Static numbers and partial data
Direct publisher deals typically use static tracking numbers -- one number per publisher, sometimes one per campaign. This tells you which publisher generated the call, but nothing about the upstream traffic source.
Did the call come from a Google search ad, an organic listing, a Facebook post, or a bought lead list? With a static number, you don't know. You can't close the loop back to the ad platform because you don't have the click ID.
Some sophisticated publishers will share gclid data, but this requires custom integration work and trust that the data is accurate. Most publishers treat their traffic source data as proprietary.
Verdict: RTB wins on attribution. Ring pool integration with click ID capture enables full closed-loop reporting that direct deals cannot match without significant custom engineering.
When direct deals still make sense
Despite RTB's advantages across most dimensions, direct deals have legitimate use cases:
Exclusive high-volume sources. If a publisher generates 1,000+ calls/day in your vertical with proven 40%+ conversion rates, an exclusive direct deal protects that supply from competition. The premium you pay is insurance against losing access.
Regulated verticals. In verticals like healthcare or financial services where compliance requirements are strict, direct relationships with vetted publishers give you more control over the consumer experience and disclosure requirements.
Test-before-you-bid. Some buyers use direct deals to evaluate new verticals or geos before committing to RTB campaigns. Lower volume, fixed pricing, and a single-publisher relationship simplify initial testing.
Relationship leverage. Long-standing publisher relationships can unlock benefits that exchanges can't provide -- early access to new traffic sources, custom IVR flows, dedicated call center capacity during peak periods.
The bottom line
For most demand-side call buyers optimizing for scale and efficiency, RTB is the better model. You set the price of every call. Checks before the bid prevent bad spend. Exchange volume lets you scale fast. Changes take effect on the next call. And ring pools close the attribution loop.
Direct deals remain valuable for exclusive supply relationships and regulated verticals, but they shouldn't be your primary procurement channel if you're buying more than a few thousand calls per month.
The optimal strategy for large buyers: run 70-80% of volume through RTB for efficiency and scale, and maintain direct relationships with your top 3-5 publishers for exclusive, high-converting supply.