Lesson 2 of 5 · 9 min read · advanced
Conversion APIs and value signals: teaching the ad platform what a click earned
How feed revenue is sent back to Meta, TikTok and Taboola through conversion APIs, why value beats a simple count, and the timing limits to respect.
Ad platforms do not just deliver your ads. Their bidding systems decide, for every impression, how much to bid on your behalf, based on how likely that person is to do the thing you told the platform you want. If you tell it nothing, it finds cheap clicks. If you tell it which clicks earned money, and how much, it goes looking for more people like those. Sending that information back is the job of a Conversions API.
Imagine a fishing guide who takes your boat out each morning. If you only tell him how many fish you caught, he steers towards the shoals of tiny ones. If you tell him the weight of each fish, he learns where the big ones are. A count is a conversion signal. A weight is a value signal.
What counts as a conversion here
A shop's conversion is a sale. An arbitrageur has nothing to sell, so the event that matters is the monetised click: the visitor clicked a sponsored result and the feed earned. Operators usually map that to a standard event the platform already understands, most often a purchase event, with the estimated revenue as the value. Earlier events, such as a click on a related search term, can be sent too, as weaker but faster signals.
How the signal gets back
- Keep the platform's click identifierWhen someone clicks a Meta ad, the landing URL carries an fbclid value. Meta's developer documentation explains that this becomes the fbc parameter, stored in a cookie on your domain, and that it should be sent back as it is, not hashed. TikTok appends its own identifier (ttclid) and Taboola passes a click ID you request in the tracking URL. Your tracker stores these beside its own Click ID.
- Wait for revenueThe feed provider reports what the visit earned, by postback or report pull.
- Send a server eventYour tracker calls the platform's API: Meta's Conversions API, TikTok's Events API, or the server-to-server conversion endpoint that native networks such as Taboola provide. The call says: this event, at this time, for this click, worth this much, in this currency.
- The platform matches and learnsThe platform ties the event to the ad that produced the click, shows it in your reports, and feeds it to bidding.
Why value matters more than count
Here is a worked example with made-up numbers. Two ad sets each spend $300 and each produce 400 monetised clicks. By count they look identical: $0.75 per conversion. But ad set A's clicks landed on insurance keywords and earned $1.10 each, so $440 of revenue and a profit of $140. Ad set B's clicks landed on recipe keywords and earned $0.50 each, so $200 of revenue and a loss of $100. A platform told only the count will treat them as equals. A platform told the value can shift budget to A. That is value-based bidding, and it is why operators send revenue, not just a tick.
| Spend | Monetised clicks | Cost per conversion | Revenue per click | Revenue | Profit | |
|---|---|---|---|---|---|---|
| Ad set A | $300 | 400 | $0.75 | $1.10 | $440 | +$140 |
| Ad set B | $300 | 400 | $0.75 | $0.50 | $200 | -$100 |
The timing problem
Bidding systems learn best from fast feedback. Feed revenue is slow: a first estimate may appear within the hour, a better one some hours later, and the finalised figure days or weeks after that (see revenue reporting delay). Operators therefore face a trade-off.
Send early estimates
- The platform learns the same day
- Values may be revised later, up or down
- Risk of teaching the algorithm on numbers that do not hold
Wait for firmer revenue
- Values are closer to what you will be paid
- The platform learns hours later
- Events for old clicks may fall outside the platform's time limits
Most settle on a middle path: send one event per click once a reasonably stable estimate exists, and send it once. Meta's documentation describes how an event ID is used to spot duplicates when the same event arrives from both the browser pixel and the server, and TikTok recommends the same pairing of pixel and Events API with deduplication. If your tracker sends a second event every time the estimate changes, the platform may count two conversions. Check how your tool handles updates.
Using the signal
- Optimise for the event. Tell the campaign to optimise for the purchase-style event, not for link clicks, once enough events are flowing.
- Optimise for value. Where the platform offers it, a value goal such as Target ROAS asks for revenue relative to spend instead of a number of events.
- Watch volume. Bidding systems need a steady stream of events. A campaign that produces a handful of conversions a day will stay in its learning phase and behave erratically.
- Reconcile weekly. Compare the value the platform recorded with the finalised revenue you were paid. A widening gap means your estimates are too optimistic.
Key takeaways
- A conversions API sends server-side events to the ad platform so its bidding can learn from real outcomes.
- In search arbitrage the conversion is the monetised click, and the value is the feed revenue for that click.
- Value signals let the platform tell a $1.10 click from a $0.50 click; counts alone cannot.
- Feed revenue is slow and revised, while platforms have time limits, such as 7 days on Meta, and need each event once.
- Reported values must be honest and collected with valid consent; fake or inflated events backfire.
Questions people ask
What is the Meta Conversions API used for in search arbitrage?
It lets your tracker tell Meta, server to server, that a particular ad click later produced feed revenue, and how much. Meta matches the event to the ad using the click identifier it attached to the landing URL. Its bidding then favours audiences and placements whose clicks earn more. Without it, Meta can only optimise for cheap clicks, which is rarely the same as profitable ones.
Should I send estimated or final revenue to the ad platform?
Usually a reasonably stable estimate, sent once per click. Final revenue can take days or weeks, by which time the platform may no longer accept the event (Meta rejects events older than 7 days) and the learning value is gone. The cost is that estimates get revised. Reconcile reported value against finalised revenue each week and adjust if the estimates run high.
What is value-based bidding?
It is a bidding mode where the ad platform aims for revenue, not a number of conversions. You send a value with each conversion event, and the platform bids more for people likely to produce higher values. For arbitrage this matters because two clicks that cost the same can earn very different amounts depending on the keyword and advertiser demand behind them.
Does TikTok have a conversions API?
Yes. TikTok calls it the Events API. It accepts conversion events from your server for web, app and offline activity, and TikTok recommends running it alongside the TikTok Pixel with event deduplication so that one conversion is not counted twice. Trackers used in search arbitrage typically connect to it to send feed revenue back, as they do with Meta.