Definition: A Responsive Search Ad (RSA) is the primary text ad format in Google Search Ads campaigns, introduced to replace the older Expanded Text Ad (ETA). Advertisers provide up to 15 headline options (30 characters each) and up to 4 description options (90 characters each). Google’s machine learning system then dynamically assembles combinations of these assets — selecting up to 3 headlines and 2 descriptions — and tests different permutations to identify which combinations produce the best click-through and conversion rates for each individual user and query context.
Why It Matters: RSAs replaced Expanded Text Ads as the only creatable Search ad format from June 2022, making them the standard unit of Google Search advertising. Their adaptive nature means a single RSA effectively runs multiple ad variations simultaneously, continuously learning which asset combinations resonate with different audience segments and query types. For advertisers, this reduces the manual work of A/B testing individual ad variants while providing broader coverage of different user intents. However, RSAs require thoughtful headline and description writing — Google’s AI can only work with the assets provided, so poorly written inputs produce poor outputs.
How It Works: RSAs are created in Google Ads at the ad level within a Search campaign’s ad group. The advertiser enters multiple headlines and descriptions, and can optionally “pin” specific assets to always appear in a fixed position (useful for ensuring brand name or key USP always shows). Google tracks each asset’s performance and assigns ratings (Best, Good, Low) based on how individual assets perform relative to others in the same ad. The ad strength indicator (Poor/Average/Good/Excellent) encourages advertisers to add variety to their assets — similar headlines reduce the system’s ability to test meaningfully different combinations. Regularly reviewing asset performance reports and replacing Low-rated assets improves overall RSA performance over time.
Related: Google Ads, Ad Assets, Ad Extensions, Quality Score, Responsive Display Ad