"Google Publishes Every Advertiser's Ads. Here Is the Keyless API Behind the Page"

If you have ever wanted to see every Google ad a competitor is running, Google already gives you the data: the Ads Transparency Center lists the live creatives of every verified advertiser, across Search, Display, and YouTube. What it does not give you is an export button.

The page itself, though, runs on a small set of JSON RPC endpoints that work without a login, a cookie, or an API key. Here is how they fit together, including the one undocumented field that cost me an hour.

Finding an advertiser

Advertisers are identified by IDs that start with AR. You resolve a brand name to IDs with a POST:

POST https://adstransparency.google.com/anji/_/rpc/SearchService/SearchSuggestions?authuser=0