Keywords API

What is the Kwinside Keyword Research API?

The Kwinside Keyword Research API returns keyword suggestions and monthly search volumes for millions of keywords across six languages — English, German, Italian, Spanish, French and Russian. You call a single REST endpoint, GET /api/v1/keywords, with a seed keyword and a language code, and it responds with related keywords and their search-volume figures drawn from a database of billions of keywords. Requests authenticate with your API key. Pricing is pay-as-you-go at $0.002 per request (about $2,000 per million) or a monthly plan, and you can test it free with 20 requests per day, no card required. Use it to build keyword-research features, expand seed lists, estimate demand, or automate research that would otherwise be manual.

Last updated: June 2026

This API is used to get search volume data for the list of the provided keywords and general keyword suggestions.

Competitors by keyword

GET /api/v1/serp/keywords/competitors

Get the competitor domains and pages that rank for a given keyword in the chosen search engine — each with its SERP position, page URL and title. Narrow to a specific keyword with kw_filter.

Parameters description:

Parameters required Description
serequiredsearch engine ID
datesrequiredcomma-separated dates: 2019-09-02,2019-09-09
size, offset—use these parameters to set the exact count of keywords in response and pagination
kw_filter—filter keyword
top_filter—available values : 1, 3, 10, 30, 50, 100 (default value : 100)
keyrequiredan API key that you can get in your account

Sample of a URI request:

</>GET
1https://kwinside.com/api/v1/serp/keywords/competitors?se=1&kw_filter=seo&dates=2026-05-24,2026-06-24&size=10&top_filter=100&key=example

Response:

{ }200 · JSON
{
  "credits_info": {
    "credits_used": 1,
    "credits_remaining": 19
  },
  "data": {
    "total": 97,
    "results": [
      {
        "id": "55fee3cc6f42e05134c5037f2b06bc9e",
        "pos": 1,
        "site": "developers.google.com",
        "page": "search%2Fdocs%2Ffundamentals%2Fseo-starter-guide",
        "title": "Search Engine Optimization (SEO) Starter Guide",
        "prop": 10,
        "https": true,
        "www": false
      },
      {
        "id": "d3d4ec41e88e6d0563865fafc7cd909e",
        "pos": 3,
        "site": "en.wikipedia.org",
        "page": null,
        "title": "Search engine optimization",
        "prop": 10,
        "https": true,
        "www": false
      },
      {
        "id": "f9cbc78b459a3b8e5f4e726a0c89d1f5",
        "pos": 6,
        "site": "moz.com",
        "page": "learn%2Fseo%2Fwhat-is-seo",
        "title": "What Is SEO? Search Engine Optimization Best Practices",
        "prop": 10,
        "https": true,
        "www": false
      }
    ]
  }
}

Frequently asked questions

Is there a free keyword API tier?
Yes. Every account includes 20 free Keyword API requests per day, and the test keywords test, apple, samsung and nokia are always free.
How much does the Keyword Research API cost?
Plans or pay-as-you-go at $0.002 per request ($2000 per 1,000,000), with a $20 minimum top-up.
Which languages does the keyword database cover?
English, German, Italian, Spanish, French and Russian.
What does the Keyword API return?
A list of keyword suggestions with their monthly search volume for any seed keyword.

Search Engine API · Best Pages API · SERP API · Competitors API