Every platform publishes its ads. Here is how to read them.

What an ad library is

An ad library is a public archive, published by the platform itself, of the advertising running on it. Anyone can search it. Nobody needs an advertising account, and the advertiser is never told that someone looked.

That last point is what makes them extraordinary. Every competitor you have is required to publish their creative, their offer, their copy and their landing page to a database you can open in a browser tab — for free, at any hour, with no negotiation and no vendor. There is no equivalent anywhere else in business. You cannot look up a rival's pricing model or their roadmap, but you can read every ad they are paying to show.

Marketers use them for the obvious things: seeing what a competitor is testing, checking whether a campaign has launched, collecting creative for a swipe file, and reading a market's positioning end to end before writing a word of their own.

Why every platform suddenly has one

These archives were not built for marketers. They exist because of politics, and specifically because of political advertising.

Facebook opened its ad archive in 2018, under sustained scrutiny of how political ads had been bought and targeted on the platform. Google published political advertising disclosures the same year. Both started as narrow political-transparency tools and were widened afterwards.

The second wave came from Europe. The Digital Services Act obliges very large online platforms to maintain public repositories of the ads they carry, and that obligation is why TikTok, LinkedIn and others now publish libraries at all — and why so many of them are richer for European ads than for the rest of the world. When you notice that a library shows targeting data for an EU campaign and nothing for the same advertiser's US campaign, you are looking at the shape of the law rather than a design decision.

It also explains the strangest asymmetry in these tools: spend is disclosed for political and election advertising and almost never for commercial advertising. Nobody legislated a right to know what a shoe company spends.

What this looks like on a real brand

The differences between these libraries stop being abstract the moment you run the same kind of search on each one. Every example below was checked in July 2026 and can be repeated in a browser tab in under a minute.

Notice that each library fails differently on the way in. Meta drowns a common word in other people's ads, Google splits one brand across dozens of legal entities, TikTok answers an American question with an empty page, and LinkedIn matches a company name loosely enough to hand you three strangers. Knowing which failure you are looking at is most of the skill.

• Meta — searching Warby Parker for active US ads returns roughly 420 results, nearly all from the brand's own Page, with several marked as running multiple versions of one creative. Search Ridge instead and you get tens of thousands, because the word is common and the search matches ad copy.
• Google — the domain ikea.com resolves to more than thirty separate verified advertiser accounts, including IKEA Deutschland, Ikea Iberica and IKEA North America Services, alongside WPP Media India and Dentsu Finland buying on IKEA's behalf.
• YouTube — squarespace.com shows roughly four thousand ads across all Google platforms, and roughly nine hundred once the YouTube filter is applied. Duolingo is the inverse: most of what it runs on Google is video.
• TikTok — Zalando returns nothing at all with the target country set to the United States, and more than a thousand ads set to Germany, filed under the registered name Zalando SE.
• LinkedIn — searching Canva also returns Canvas Forum, Canvas Homes and Canvas Worldwide, because the company field matches loosely.

What none of them will tell you

Before you build a research habit on these tools, it is worth being clear about the questions they cannot answer, because the gaps are the same everywhere and none of them is going to close.

There is no spend and no performance data for commercial advertising. No impressions, no clicks, no click-through rate, no conversions, no keywords, no bids. Spend appears only where an election or political disclosure law compels it, which is why you can read what a party paid to reach voters and not what a retailer paid to reach shoppers. Every tool that quotes you a competitor's ad spend is estimating it from something else.

There is no history you control. Outside specific regulated windows — Meta's political and EU archives, TikTok's post-2022 record, LinkedIn's rolling year — a commercial ad exists in the record only while it runs. This is the one that catches people out in practice: advertisers rotate creative constantly, and a campaign you found in March can be entirely absent in July with nothing to mark that it was ever there.

And there is no workflow. Nothing diffs one visit against the last, nothing alerts you when a competitor launches, and nothing exports in a form you can keep. Those three are covered below, because they are what actually decides whether your research survives past week three.

What they all have in common

The five libraries differ in scope and generosity, but they fail in the same four ways, and the failures are structural rather than oversights.

None of them diffs. Every library shows a flat list of what exists, so the ad launched yesterday and the ad that has run for a year look identical, and the ad quietly killed last week simply is not there any more — with nothing to mark its absence. The change is the intelligence, and the change is exactly what is not published.

None of them alerts. A competitor can launch a campaign the day after you check and you will not know until you happen to look again. None of them exports properly, so anything you want to keep gets screenshotted. And most of them forget: outside specific regulated windows, a commercial ad disappears from the record when the advertiser switches it off.

The result is a research habit that works for two or three weeks. Everyone starts with a calendar reminder and a folder of screenshots. Almost nobody is still doing it in month three.