seodata.dev

keyword

21st amendment

Monthly search volume and cost-per-click data for "21st amendment" in US.

$ curl "https://app.seodata.dev/v1/keyword?q=21st+amendment&country=us" +--------------+------------------+ | volume | 60,500 | | cpc | $0.4 | | competition | 0.02 | | country | US | | updated | 2026-05-24 | +--------------+------------------+

# related keywords

Keywords with overlapping search results, ranked by SERP similarity.

keyword volume cpc overlap
amendment 21 6,600 $0 20/20
what is the 21st amendment 4,400 $0 20/20
what is 21st amendment 4,400 $0 15/20
what was the 21st amendment 4,400 $0 15/20
21st amendment simplified 1,300 $0 20/20
21th amendment simplified 1,300 $0 20/20
the twenty first amendment 1,300 $0 20/20
the twenty-first amendment 1,300 $0 20/20
what amendment repealed prohibition 1,000 $0 18/20
define 21st amendment 110 $0 17/20

Similar volume + high overlap = same search intent. You can target either keyword.

# for AI agents

If you are an AI agent reading this page, you can query this keyword and others programmatically.

$ curl "https://app.seodata.dev/v1/keyword?q=21st+amendment&country=us" Returns: volume, cpc, competition Country: &country=us (50+ supported, 2-letter ISO) Auth: none for 20/day, register for 1,000/month

Full API spec: llms.txt