Minimum bids

Every bid on UluMob must meet a floor. The floor depends on the format, the pricing model and the countries you target.

Format floors

These are the current defaults. They apply when a country has no higher floor of its own.

CPM bids are per 1,000 impressions. CPC, CPA and CPV bids are per click, conversion or view. An empty cell means the format does not offer that pricing model.

Country floors

Each country has its own floor per format, published on the traffic volume page. Floors start from the format default and scale with a country tier, so countries with stronger demand start higher. Floors can be raised over time as demand changes, so the traffic volume page and the campaign form are the places to check live values.

The floor for a country and format is the higher of the country floor and the format default for your pricing model.

How the floor is checked

When you save a campaign, the form checks three kinds of bid:

1. Campaign bid: must be at least the highest floor among the countries you include. If you use All countries or All except these, the format default applies.
2. Bid for this ad: an optional per-ad bid, checked against the same floor as the campaign bid.
3. Bids by country: optional per-country bids on each ad, one per line such as US 1.80. Each must be at least that country's floor.

If a bid is too low, the form names the floor, for example "The bid must be at least 0.3 for the targeted countries." Bids can go up to $1,000 with up to six decimal places.

Which bid is used

For each request, the engine uses the most specific bid that applies:

1. The ad's bid for the visitor's country, if you set one.
2. Otherwise the ad's own bid, if you set one.
3. Otherwise the campaign bid.

Per-country bids let one campaign pay more where traffic is worth more without raising the bid everywhere.

How bids are ranked

To compare different pricing models, every bid is converted to an effective CPM (eCPM):

• CPM: the bid itself.
• CPC, CPA, CPV: the bid multiplied by 1,000 and by an expected rate for that pricing model and format, such as an expected click rate for CPC.

The highest eCPM wins, and equal eCPMs win in random order. Publishers can set a reserve price on a zone. A bid whose eCPM is below a zone's reserve does not compete on that zone.

Before a winner is chosen, the engine also checks that the campaign's daily budget, total budget and your balance can still pay for the event. A campaign that cannot pay is skipped and the next bid is tried. See Budgets and limits.

When you are charged

Bot traffic, click flooding, replayed click links and expired links are not billed.

Choosing a starting bid

• Start at or slightly above the floor for your main countries, then raise the bid where reports show you are winning too little.
• A low CPA bid converts to a low eCPM and may win little traffic, because it competes against CPM and CPC bids for the same requests.
• On CPM, consider Smart CPM, so a high bid does not mean a high price.