SEO API · Keyword Clustering

Keyword Clustering

Group a keyword's universe into topic clusters by SERP overlap.

Give a seed keyword and get back topic clusters: we expand it into its suggestion universe, fetch the live SERP for each, and group keywords that share ranking pages. Ideal for content planning, silo/hub-and-spoke architecture and pillar pages.

POST /api/v1/keywords/clustering $0.25 / request

Get API Key

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Open Playground

curl

curl -X POST https://seonio.com/api/v1/keywords/clustering \
  -H "Content-Type: application/json" \
  -H "X-API-Key: $SEONIO_API_KEY" \
  -d '{"country": "us", "keyword": "keyword research"}'

Sample response

{
  "clusters": [
    {
      "keywords": [
        {
          "text": "keyword research",
          "volume": 550000
        },
        {
          "text": "keyword research tool",
          "volume": 90500
        },
        {
          "text": "free keyword research",
          "volume": 33100
        }
      ],
      "name": "keyword research",
      "shared_urls": [
        "https://ahrefs.com/keyword-generator",
        "https://moz.com/explorer"
      ],
      "size": 3,
      "volume": 673000
    },
    {
      "keywords": [
        {
          "text": "long tail keywords",
          "volume": 27100
        },
        {
          "text": "long tail keyword research",
          "volume": 14100
        }
      ],
      "name": "long tail keywords",
      "shared_urls": [
        "https://backlinko.com/long-tail-keywords"
      ],
      "size": 2,
      "volume": 41200
    }
  ],
  "country": "us",
  "keyword": "keyword research"
}

Request and response

The full contract for /api/v1/keywords/clustering — what to send and what comes back.

Request body

keyword string required

The seed keyword to cluster, e.g. "keyword research".

country string optional

Two-letter ISO country code for the SERPs (default "us").

Response fields

`keyword`	string	The seed keyword that was clustered.
`country`	string	The country the SERPs were fetched for. Supported countries `in` India `vn` Vietnam `us` United States `gb` United Kingdom `de` Germany `pk` Pakistan `bd` Bangladesh `ca` Canada `tr` Turkiye `id` Indonesia `fr` France `es` Spain `nl` Netherlands `it` Italy `au` Australia `ae` United Arab Emirates `ph` Philippines `ch` Switzerland `jp` Japan `ng` Nigeria `eg` Egypt `th` Thailand `za` South Africa `mx` Mexico `sg` Singapore `ke` Kenya `at` Austria `ma` Morocco `pl` Poland `dk` Denmark `my` Malaysia `sa` Saudi Arabia `lk` Sri Lanka `ro` Romania `gh` Ghana `fi` Finland `se` Sweden `be` Belgium `br` Brazil `ie` Ireland `bg` Bulgaria `gr` Greece `nz` New Zealand `rs` Serbia `dz` Algeria `no` Norway `hu` Hungary `ar` Argentina `pt` Portugal `cz` Czechia
`clusters[]`	object[]	Topic clusters, largest by volume first.
`clusters[].name`	string	The cluster's head keyword (its highest-volume member).
`clusters[].volume`	integer	Combined monthly search volume of the cluster.
`clusters[].size`	integer	Number of keywords in the cluster.
`clusters[].keywords[]`	object[]	The member keywords, each as { text, volume }.
`clusters[].shared_urls[]`	string[]	Pages that rank across the cluster's members (the SERP overlap that grouped them).

Code examples

Copy, paste, swap in your API key.

curl -X POST https://seonio.com/api/v1/keywords/clustering \
  -H "Content-Type: application/json" \
  -H "X-API-Key: YOUR_API_KEY" \
  -d '{"country": "us", "keyword": "keyword research"}'

import requests

resp = requests.post(
    "https://seonio.com/api/v1/keywords/clustering",
    headers={"X-API-Key": "YOUR_API_KEY"},
    json={"country": "us", "keyword": "keyword research"},
)
print(resp.json())

const resp = await fetch("https://seonio.com/api/v1/keywords/clustering", {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
    "X-API-Key": "YOUR_API_KEY",
  },
  body: JSON.stringify({"country": "us", "keyword": "keyword research"}),
});
console.log(await resp.json());

Playground

Run a real /api/v1/keywords/clustering request. No key? We show the real sample result so you can still inspect the shape.

API key

JSON body

Leave the API key empty to load the built-in sample response.

Request

POST /api/v1/keywords/clustering

sample mode

What developers build with it

Common ways Keyword Clustering ends up in production.

Building topic clusters and content silos from one seed keyword.

Planning pillar pages and their supporting articles.

Mapping a keyword universe to information architecture.

Status codes

The same predictable contract on every endpoint.

`200`	Success. The lookup completed and was charged, even if the response is empty.
`401`	Missing or unknown API key.
`402`	Not enough balance on the account.
`422`	Invalid request body (wrong shape or types).
`429`	Rate limit exceeded (fixed-window default: 30 requests / 3 seconds).

Other endpoints

Explore the rest of the SEO API.

Keyword Research

/api/v1/keywords/global

Keyword Suggestions

/api/v1/keywords/suggestions

Keyword Metrics by Country

/api/v1/keywords/country

SERP

/api/v1/serp/country

SERP Scraper

/api/v1/serp/scraper

Scraper

/api/v1/scraper

Website Traffic

/api/v1/website/traffic

Website Ranking

/api/v1/website/ranking

URL Stats

/api/v1/url/stats

Website Stats

/api/v1/website/stats

Website Backlinks

/api/v1/backlink/website

URL Backlinks

/api/v1/backlink/url

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FAQ

Simple answers for developers using the API.

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