Meta Ads (Facebook, Instagram, Messenger, Threads and the Audience Network) runs an auction for every ad slot. Meta picks the ad with the highest total value: your bid, multiplied by how likely the person is to take your chosen action, plus a quality and user-experience score. In 2026 most of the targeting work is automated — the system decides who sees which ad mostly from your creative and your conversion data.
The auction in one formula
Total value = advertiser bid × estimated action rate + ad quality.
- Bid: what you are willing to pay, set by your bid strategy (lowest cost, cost cap, bid cap, ROAS goal).
- Estimated action rate: Meta's prediction that this person will take your optimisation event — purchase, lead, install.
- Ad quality: feedback signals such as hides and reports, and low-quality attributes like engagement bait or withheld information.
An ad with a lower bid can still win if Meta predicts it will convert better and users like it more.
Andromeda and GEM: how ads are chosen
Meta's ad delivery now works in two stages, according to Meta's engineering communications and industry analyses:
- Retrieval (Andromeda) narrows millions of eligible ads down to a shortlist of candidates for each person.
- Ranking — including Meta's generative recommendation model (GEM) introduced in late 2025 — scores the shortlist and picks the winner.
The practical consequence: creative is targeting. Meta reads your image, video and copy to understand who an ad is for. Near-identical creatives tend to be treated as the same ad and compete with each other. Diverse concepts — different angles, formats and hooks — give the system more distinct options to match to different people.
Advantage+ in practice
Advantage+ is Meta's family of automated features:
- Advantage+ campaigns for sales and app installs, with automated audience, placements and budget allocation.
- Advantage+ audience, where your targeting inputs act as suggestions rather than hard limits.
- Advantage+ placements across Facebook, Instagram, Messenger, Threads and the Audience Network.
- Advantage+ creative enhancements that adjust brightness, crop, text or add music automatically. Review these for regulated or affiliate offers — automatic changes can break compliance.
You still control: the offer, the creative, the optimisation event, the budget, exclusions, countries and the landing page.
The learning phase
After launch or a significant edit, an ad set enters the learning phase while Meta explores who converts. Meta's long-standing guidance is roughly 50 optimisation events per ad set per week to exit learning; some campaign types may need fewer, and the exact thresholds change — check Meta's Business Help Center. To get through learning faster:
- Consolidate: fewer ad sets with more budget each.
- Avoid frequent edits — big budget changes, new targeting or creative swaps can restart learning.
- If you cannot get enough purchases, optimise for a higher-funnel event that still correlates with revenue.
Why the Conversions API matters
Browser tracking (the Meta Pixel) loses signal to ad blockers, cookie restrictions and iOS privacy controls. The Conversions API (CAPI) sends events from your server directly to Meta. Running both, with deduplication by event ID, gives the system more complete data — and better data means better delivery. For apps, connect your MMP (AppsFlyer, Adjust, Singular) so installs and in-app events flow to Meta.
Rules affiliates must respect
Meta is strict with affiliate-style advertising:
- Landing page and ad must match. Misleading claims, fake news layouts and fake endorsements lead to rejections and account restrictions.
- Restricted categories: financial products, crypto, gambling, dating, health and weight loss have special requirements or need authorisation.
- Special ad categories (credit, employment, housing, social issues) limit targeting.
- Cloaking and circumventing review lead to permanent bans of accounts, pages and Business Managers.
A practical launch checklist
- Pixel plus Conversions API installed, with event deduplication.
- Domain verified and events prioritised as required.
- One campaign per objective; one to three ad sets; several genuinely different creatives per ad set.
- Optimise for the deepest event you can reach at volume.
- Let it learn; judge on at least three to seven days of data, not one.
- Refresh creative when frequency rises and results fall.
FAQ
What is Meta Andromeda?
Andromeda is the name Meta uses for the retrieval system that selects a shortlist of candidate ads for each person before final ranking. It makes creative diversity more important than detailed audience targeting.
Is the Meta Pixel enough in 2026?
Usually not. Use the Pixel together with the Conversions API so events lost in the browser are still sent from your server, and deduplicate them by event ID.
How many creatives should I test on Meta?
There is no official number, but several distinct concepts per ad set — different hooks, formats and messages — work better than many small variations of the same image.
Can affiliates run Meta ads?
Yes, if the ads, landing pages and offer comply with Meta's advertising standards and the advertiser's terms. Regulated categories need extra authorisation.
Sources
- Meta Business Help Center (opens in a new tab)
- Medium — Meta ads strategy 2026: Andromeda and GEM (opens in a new tab)
Published 25 October 2026 by the ClickSpero Editorial Team. Platform features, fees and policies change often — check the provider’s current terms before you rely on a number. Third-party names are trademarks of their owners; no endorsement is implied.