Related Keywords

Discover semantically related keywords and variations with search volume, CPC, and difficulty.

POST/v1/seo/keywords/related

from $0.03 + $0.03/100 keywords

Pricing

$0.03 per call + $0.03 per 100 keywords, rounded up to the next whole cent.

Keywords returned	Cost per call
1 keyword	$0.04
10 keywords	$0.04
50 keywords	$0.05
100 keywords	$0.06
250 keywords	$0.11
500 keywords	$0.18
1,000 keywords	$0.33

Billed on the number of results actually returned, not the number requested. Failed calls are never charged.

Usage

const res = await fetch('https://api.yepapi.com/v1/seo/keywords/related', {
  method: 'POST',
  headers: {
    'x-api-key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({ keyword: 'email marketing', limit: 50 }),
});
const { data } = await res.json();
console.log(data);

curl -X POST https://api.yepapi.com/v1/seo/keywords/related \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"keyword": "email marketing", "limit": 50}'

Request Body

Parameter	Type	Required	Description	Default
`keyword`	`string`	Yes	Seed keyword to find related terms for (e.g., `"email marketing"`)	—
`limit`	`number`	No	Maximum number of related keywords to return	`50`
`location_code`	`number`	No	Target country code (e.g., `2840` for US). See Location Codes.	`2840`
`language`	`string`	No	ISO language code (e.g., `en`, `es`)	`"en"`

Narrow and order results with filters, match, and sort. Filter on the same friendly field names returned in the response — volume, cpc, difficulty, competition, competitionLevel, intent, keyword, plus words and length (keyword length).

{
  "filters": [
    { "field": "volume", "op": ">=", "value": 500 },
    { "field": "difficulty", "op": "<", "value": 40 },
    { "field": "intent", "op": "in", "value": ["informational", "commercial"] }
  ],
  "match": "all",
  "sort": ["volume:desc"]
}

See Keyword Filters for the full list of fields, operators (>, >=, <, <=, =, !=, in, nin, like, not_like), and limits (max 8 filters, 3 sort rules).

Response

{
  "ok": true,
  "data": {
    "seed": "email marketing",
    "keywords": [
      {
        "keyword": "email marketing",
        "volume": 18100,
        "cpc": 46.41,
        "difficulty": 73,
        "competition": 0.17,
        "competitionLevel": "LOW",
        "intent": "informational",
        "avgBacklinks": 5295.1,
        "avgReferringDomains": 708.5,
        "serpFeatures": [
          "images",
          "organic",
          "peopleAlsoAsk",
          "video",
          "perspectives",
          "relatedSearches"
        ],
        "totalResults": 2370000000,
        "trend": [
          { "month": "2026-03", "volume": 27100 },
          { "month": "2026-02", "volume": 14800 },
          { "month": "2026-01", "volume": 12100 }
        ]
      },
      {
        "keyword": "email marketing jobs",
        "volume": 2900,
        "cpc": 3.95,
        "difficulty": 7,
        "competition": 0.12,
        "competitionLevel": "LOW",
        "intent": "informational",
        "avgBacklinks": 177.4,
        "avgReferringDomains": 6.7,
        "serpFeatures": [
          "jobs",
          "organic",
          "peopleAlsoAsk",
          "relatedSearches"
        ],
        "totalResults": 1840000000,
        "trend": [
          { "month": "2026-03", "volume": 2400 },
          { "month": "2026-02", "volume": 2400 },
          { "month": "2026-01", "volume": 2900 }
        ]
      }
    ]
  }
}

Response Fields

Field	Type	Description
`ok`	`boolean`	Whether the request succeeded
`data.seed`	`string`	The seed keyword used to find related terms
`data.keywords`	`object[]`	Array of related keyword results
`data.keywords[].keyword`	`string`	The related keyword
`data.keywords[].volume`	`number`	Average monthly search volume
`data.keywords[].cpc`	`number`	Cost per click in USD
`data.keywords[].difficulty`	`number`	SEO difficulty score (0-100)
`data.keywords[].competition`	`number`	PPC competition index (0-1)
`data.keywords[].competitionLevel`	`string`	Competition category (`LOW`, `MEDIUM`, `HIGH`, or `unknown`)
`data.keywords[].intent`	`string`	Search intent (`informational`, `commercial`, `navigational`, `transactional`, or `unknown`)
`data.keywords[].avgBacklinks`	`number`	Average number of backlinks for top-ranking pages
`data.keywords[].avgReferringDomains`	`number`	Average number of referring domains for top-ranking pages
`data.keywords[].serpFeatures`	`string[]`	SERP features present for this keyword (e.g., `images`, `video`, `jobs`, `peopleAlsoAsk`)
`data.keywords[].totalResults`	`number`	Total number of search results
`data.keywords[].trend`	`object[]`	Monthly search volume trend data
`data.keywords[].trend[].month`	`string`	Month in `YYYY-MM` format
`data.keywords[].trend[].volume`	`number`	Search volume for that month

Under the Hood

Under the hood, this queries our SEO data engine for semantically related terms. These are terms searchers also look for, not just string variations of the seed keyword.