SEO API

Keyword Research

Volume, CPC, competition and a 12-month trend for up to 100 keywords in one call.

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POST /api/v1/keywords/global$0.001 / keywordAuth: X-API-Key header

seonio / rest apiFrom the API docs

RequestPOST /api/v1/keywords/global

curl -X POST https://seonio.com/api/v1/keywords/global \
  -H "Content-Type: application/json" \
  -H "X-API-Key: $SEONIO_API_KEY" \
  -d '{"keywords": ["keyword research", "seo tools", "domain authority checker"]}'

Response200 OK

{
  "keywords": [
    {
      "text": "keyword research",
      "volume": 550000,
      "cpc": 37,
      "low_cpc": 37,
      "high_cpc": 212,
      "competition": 18,
      "monthly_trend": [
        {
          "month": "2026-08",
          "value": 450000
        },
        {
          "month": "2026-07",
          "value": 201000
        },
        {
          "month": "2026-06",
          "value": 27100
        }
      ],
      "source": "google_ads"
    },
    {
      "text": "seo tools",
      "volume": 110000,
      "cpc": 86,
      "low_cpc": 86,
      "high_cpc": 455,
      "competition": 53,
      "monthly_trend": [
        {
          "month": "2026-08",
          "value": 301000
        },
        {
          "month": "2026-07",
          "value": 90500
        },
        {
          "month": "2026-06",
          "value": 90500
        }
      ],
      "source": "google_ads"
    },
    {
      "text": "domain authority checker",
      "volume": 135000,
      "cpc": 41,
      "low_cpc": 41,
      "high_cpc": null,
      "competition": 76,
      "monthly_trend": [
        {
          "month": "2026-08",
          "value": 110000
        },
        {
          "month": "2026-07",
          "value": 110000
        },
        {
          "month": "2026-06",
          "value": 110000
        }
      ],
      "source": "google_ads_estimated_months"
    }
  ]
}

Contract

What to send and what comes back

Send a list of keywords and get back the core metrics most SEO and PPC tools are built on. Ideal for keyword explorers, content planners and bulk research jobs.

Request body

Request body
Field	Type	Required	Description
`keywords`	string[]	required	1–100 keywords to look up. Billed per keyword.

Response

Response fields
Field	Type	Description
`keywords[].text`	string	The keyword. A keyword with no data is left out of the list (still billed).
`keywords[].volume`	integer	Average monthly search volume worldwide (Google Ads).
`keywords[].cpc`	integer	Cost per click in US cents: the same value as low_cpc, kept for existing clients.
`keywords[].low_cpc`	integer	Google Ads' low top-of-page bid in US cents. When source is google_ads_estimated_months it comes from a second source, which can differ.
`keywords[].high_cpc`	integer \| null	Google Ads' high top-of-page bid in US cents; null when source is google_ads_estimated_months (that source has no high bid).
`keywords[].competition`	integer	Google Ads competition index (0–100).
`keywords[].monthly_trend`	object[]	Up to 12 months of search volume, newest to oldest, each as { month: YYYY-MM, value }, labelled with the Google Ads month each value belongs to. With source google_ads the months are Google's own, from data updated since Google's latest monthly release; with google_ads_estimated_months they are dated by rule (the newest is two months before the request) and can be one month off. Until October 2026 these months were labelled one month later than the data; the values were right.
`keywords[].source`	string	"google_ads": our stored Google Ads history, exact months, served only while it is current. "google_ads_estimated_months": the same Google Ads metrics from a second source, months estimated.

Code

Copy, paste, add your key

The same request in cURL, Python and Node.js.

cURL

curl -X POST https://seonio.com/api/v1/keywords/global \
  -H "Content-Type: application/json" \
  -H "X-API-Key: YOUR_API_KEY" \
  -d '{"keywords": ["keyword research", "seo tools", "domain authority checker"]}'

Python

import requests

resp = requests.post(
    "https://seonio.com/api/v1/keywords/global",
    headers={"X-API-Key": "YOUR_API_KEY"},
    json={"keywords": ["keyword research", "seo tools", "domain authority checker"]},
)
print(resp.json())

Node.js

const resp = await fetch("https://seonio.com/api/v1/keywords/global", {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
    "X-API-Key": "YOUR_API_KEY",
  },
  body: JSON.stringify({"keywords": ["keyword research", "seo tools", "domain authority checker"]}),
});
console.log(await resp.json());

Playground

Run a real request

Send this request from your browser with your API key, or leave the key empty to see the sample response.

API key

JSON body

A successful run costs $0.001 / keyword. With no key, you see the sample response and nothing is charged.

POST /api/v1/keywords/globalSample response

{
  "keywords": [
    {
      "competition": 18,
      "cpc": 37,
      "high_cpc": 212,
      "low_cpc": 37,
      "monthly_trend": [
        {
          "month": "2026-08",
          "value": 450000
        },
        {
          "month": "2026-07",
          "value": 201000
        },
        {
          "month": "2026-06",
          "value": 27100
        }
      ],
      "source": "google_ads",
      "text": "keyword research",
      "volume": 550000
    },
    {
      "competition": 53,
      "cpc": 86,
      "high_cpc": 455,
      "low_cpc": 86,
      "monthly_trend": [
        {
          "month": "2026-08",
          "value": 301000
        },
        {
          "month": "2026-07",
          "value": 90500
        },
        {
          "month": "2026-06",
          "value": 90500
        }
      ],
      "source": "google_ads",
      "text": "seo tools",
      "volume": 110000
    },
    {
      "competition": 76,
      "cpc": 41,
      "high_cpc": null,
      "low_cpc": 41,
      "monthly_trend": [
        {
          "month": "2026-08",
          "value": 110000
        },
        {
          "month": "2026-07",
          "value": 110000
        },
        {
          "month": "2026-06",
          "value": 110000
        }
      ],
      "source": "google_ads_estimated_months",
      "text": "domain authority checker",
      "volume": 135000
    }
  ]
}

Use cases

What developers build with it

Bulk keyword explorers and research dashboards.
Content briefs that need volume and trend at a glance.
Prioritising a backlog by demand and competition.

Status codes

The same contract on every endpoint

Error responses are JSON with a "detail" field. It is a message string unless the row above says otherwise.

Status codes
Code	When
`200`	Success. The lookup completed and was charged, even if the response is empty.
`401`	Missing or unknown API key.
`402`	Not enough balance. "detail" is an object with "error", "message", "balance_required" and "balance_available". Requests still running hold their price until they finish, so a retry can succeed once they do.
`403`	The account is not verified yet, or it is locked.
`422`	Invalid request (wrong shape or types, a keyword over 200 characters, a URL the page checker cannot audit, a domain that does not exist, or a bare public suffix such as co.uk that groups many websites) — never charged. "detail" is usually a list of validation errors; an answer that retrying cannot change (such as a domain without a DNS record) is a message string with an X-Outcome header naming it: missing, unsupported, too_large or refused_input.
`429`	Rate limit exceeded, never charged. Requests per second per account by plan: 5 on a free account, 10 on Starter, 15 on Pro and 20 on Business; retry after the Retry-After header. Also the page checker's provider limit.
`503`	A data provider failed or timed out (X-Outcome: temporary). Nothing was charged; retry after the seconds in the Retry-After header.

Related endpoints

More endpoints to use with the same API key. Every one draws on the same balance.

All 21 endpoints

$0.005 / request

Keyword Difficulty

Country-specific ranking difficulty.

View docs

$0.001 / keyword

Keyword Intent

Search-intent classification for up to 100 keywords.

View docs

$0.01 / request

Keyword Demographics

Age and gender demand distribution.

View docs

$0.25 / request

Keyword Clustering

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

View docs

$0.02 / request

Keyword Suggestions

Up to 100 related keyword ideas — each with full metrics — from one seed keyword.

View docs

$0.01 / request + $0.001 / started 10 keywords

Keyword Metrics by Country

Localized metrics for up to 500 keywords in one country.

View docs

FAQ

Questions, answered

Simple answers for developers using the API.

Every endpoint has a published USD price or formula. Requests draw from the same testing, included and Extra Usage balance as website and MCP actions: testing first, then included usage, then Extra Usage expiring soonest.

API actions require a verified account with a testing balance or an active subscription balance. Create and manage API keys from your account, then send the key in the X-API-Key header.

Yes. Your account shows API usage and remaining balance, so you can track costs while building and running automated workflows.

REST API and MCP requests per second depend on your plan: 5 on a free account, 10 on Starter, 15 on Pro and 20 on Business. Website data requests from the same account count toward the same second. Requests above the limit return HTTP 429 with a Retry-After header and are not charged; wait a second and retry.

$1 testing balance · No card required

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