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POST /v1/serp/keyword-research from 60 tokens PRO API key SERP

Search a phrase and extract SEO metadata + top keywords from each…

Search a phrase and extract SEO metadata + top keywords from each result siteesults page of up to 10 results actually fetched + 2 per site successfully analyzed). searchEngine: "bing" always returns a 503. Microsoft retired the Bing Search APIs on…

POST

Request

  • x-api-key: <your-api-key>
  • Content-Type: application/json

Response 

{
  "analyzed": 27,
  "geocoded": true,
  "pagesFetched": 28,
  "results": [],
  "searchEngine": "castomapi",
  "status": "success",
  "succeeded": 2,
  "tokensDeducted": 60
}
The response below is a mock built from the endpoint's own schema — no request leaves this page. Edit the body, press Send, read the shape you will get back. Run it for real in the dashboard →

What it does

Search a phrase and extract SEO metadata + top keywords from each result siteesults page of up to 10 results actually fetched + 2 per site successfully analyzed). searchEngine: "bing" always returns a 503. Microsoft retired the Bing Search APIs on 2025-08-11. `location` is accepted but ignored (it only ever biased Bing).

Request

Body

FieldTypeRequiredDescription
countrystringyes
langstringyes
limitintegeryes
locationstringno
phrasestringyes
searchEngineenumyesOne of: google, bing.

Example request

{
  "country": "PL",
  "lang": "en",
  "limit": 10,
  "location": "<location>",
  "phrase": "<phrase>",
  "searchEngine": "google"
}

Response

FieldTypeDescription
analyzedinteger
geocodedboolean
pagesFetchedinteger
resultsarray<object>
searchEnginestring
statusstring
succeededinteger
tokensDeductedinteger

Example response

{
  "analyzed": 27,
  "geocoded": true,
  "pagesFetched": 28,
  "results": [],
  "searchEngine": "castomapi",
  "status": "success",
  "succeeded": 2,
  "tokensDeducted": 60
}

Errors

Every error answers with the same envelope: an HTTP status, a machine code and a sentence.

400The body or a parameter failed validation. The details array names the field.
401No key, a revoked key or a wrong header. Send x-api-key.
402The wallet cannot cover this call. Top up or wait for the monthly grant.
404The resource does not exist, or it is not yours. Both answer identically and cost nothing.
429Over the per-minute quota of your tier. Back off and retry.
5xxUpstream refused or timed out. The call is not billed.

Code

curl -X POST 'https://app.castomapi.com/v1/serp/keyword-research' \
  -H 'x-api-key: <your-api-key>' \
  -H 'Content-Type: application/json' \
  -d '{"country": "PL", "lang": "en", "limit": 10, "location": "<location>", "phrase": "<phrase>", "searchEngine": "google"}'
const res = await fetch('https://app.castomapi.com/v1/serp/keyword-research', {
  method: 'POST',
  headers: { 'x-api-key': '<your-api-key>', 'Content-Type': 'application/json' },
  body: JSON.stringify({"country": "PL", "lang": "en", "limit": 10, "location": "<location>", "phrase": "<phrase>", "searchEngine": "google"})
});
const data = await res.json();
console.log(data);
import { request } from 'node:https';

// Node 18+ has fetch built in
const res = await fetch('https://app.castomapi.com/v1/serp/keyword-research', {
  method: 'POST',
  headers: { 'x-api-key': '<your-api-key>', 'Content-Type': 'application/json' },
  body: JSON.stringify({"country": "PL", "lang": "en", "limit": 10, "location": "<location>", "phrase": "<phrase>", "searchEngine": "google"})
});
const data = await res.json();
console.log(data);
import requests

res = requests.post(
    'https://app.castomapi.com/v1/serp/keyword-research',
    headers={'x-api-key': '<your-api-key>'},
    json={"country": "PL", "lang": "en", "limit": 10, "location": "<location>", "phrase": "<phrase>", "searchEngine": "google"},
    timeout=30,
)
print(res.json())
<?php
$ch = curl_init('https://app.castomapi.com/v1/serp/keyword-research');
curl_setopt_array($ch, [
    CURLOPT_CUSTOMREQUEST => 'POST',
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => ['x-api-key: <your-api-key>', 'Content-Type: application/json'],
    CURLOPT_POSTFIELDS => json_encode(['country' => 'PL', 'lang' => 'en', 'limit' => 10, 'location' => '<location>', 'phrase' => '<phrase>', 'searchEngine' => 'google']),
]);
$data = json_decode(curl_exec($ch), true);
print_r($data);

Cost and limits

This operation costs from 60 tokens. A call that fails is never billed. Every account gets 1000 free tokens a month; paid balances never expire. 60 tokens per page of up to 10 results actually fetched, plus 2 per site actually analysed. Available on the PRO and Enterprise plans: this operation spends castomAPI's own keys or quota. A key on the free plan is refused with 403 and is not billed.

Rate limits per minute

No key10
Free60
Pro300
Enterprise1200

Docs → Pricing

Questions

What does Search a phrase and extract SEO metadata + top keywords from each… cost?

from 60 tokens per successful call, debited from your wallet after the response. Failed calls are free. Every account receives 1000 free tokens a month. 60 tokens per page of up to 10 results actually fetched, plus 2 per site actually analysed.

How do I authenticate?

Send your key in the x-api-key header. One key covers every metered endpoint; there is nothing to enable per endpoint.

Can I send an Authorization: Bearer token instead?

Not for a metered endpoint — those take the x-api-key header and nothing else. Bearer tokens belong to the account side: the dashboard and account APIs accept a JWT session, and castomapi-auth issues those through a standard OAuth2 handshake, with authorization code, client credentials and refresh grants. The auth service page covers it.

What are the limits?

10 requests a minute per IP with no key at all, 60 a minute on the free tier, 300 on Pro, 1200 on Enterprise. Above the no-key tier the quota is per account, across every endpoint.

OpenAPI: https://app.castomapi.com/docs/json