Free SEO API

SEO data for developers

Query domain authority, backlinks and spam scores programmatically. Free API key, no credit card, 100 requests per day.

No credit card100 req/day freeOpen web indexNo vendor lock-in

Get your API key

Enter a project name and email. Your key is generated instantly.

Endpoints

All endpoints accept GET requests and return JSON. Pass your key as a Bearer token or a query parameter.

GET/api/v1/domain-authority

Returns authority score, referring domains, total backlinks, PageRank rank, and harmonic rank for any domain.

Parameter	Type	Required	Description
domain	string	required	The domain to query (e.g. example.com)
key	string	required	Your API key (or pass as Authorization: Bearer <key>)

Request

curl "https://www.getcrawly.com/api/v1/domain-authority?domain=example.com" \
  -H "Authorization: Bearer crawly_live_your_key"

Response

{
  "domain": "example.com",
  "summary": {
    "referring_domains": 1284,
    "total_links": 9430
  },
  "score": {
    "harmonic_rank": 124500,
    "harmonic_score": 0.81,
    "pagerank_rank": 892000,
    "host_count": 460
  }
}

GET/api/v1/backlinks

Returns the full backlink profile for a domain including referring domains, individual backlinks with quality ratings, and outbound links.

Parameter	Type	Required	Description
domain	string	required	The domain to query (e.g. example.com)
key	string	required	Your API key (or pass as Authorization: Bearer <key>)

Request

curl "https://www.getcrawly.com/api/v1/backlinks?domain=example.com" \
  -H "Authorization: Bearer crawly_live_your_key"

Response

{
  "domain": "example.com",
  "summary": {
    "referring_domains": 1284,
    "total_links": 9430
  },
  "backlinks": {
    "total": 1284,
    "backlinks": [
      {
        "source_domain": "nytimes.com",
        "link_count": 14,
        "domain_rating": "High",
        "pagerank_rank": 45
      }
    ]
  },
  "outlinks": {
    "total": 312,
    "outlinks": [
      { "target_domain": "github.com", "link_count": 9 }
    ]
  },
  "score": {
    "harmonic_rank": 124500,
    "pagerank_rank": 892000,
    "host_count": 460
  }
}

GET/api/v1/spam-score

Returns a spam score (0-100) for a domain based on link density, IP diversity, and authority signals. Lower is better.

Parameter	Type	Required	Description
domain	string	required	The domain to query (e.g. example.com)
key	string	required	Your API key (or pass as Authorization: Bearer <key>)

Request

curl "https://www.getcrawly.com/api/v1/spam-score?domain=example.com" \
  -H "Authorization: Bearer crawly_live_your_key"

Response

{
  "domain": "example.com",
  "spam_score": 12,
  "risk": "Very Low",
  "signals": {
    "total_links": 9430,
    "referring_domains": 1284,
    "host_count": 460,
    "harmonic_rank": 124500
  }
}

Code examples

Use any HTTP client. No SDK required.

JavaScript

const domain = "example.com";
const key = "crawly_live_your_key";

const res = await fetch(
  `https://www.getcrawly.com/api/v1/domain-authority?domain=${domain}`,
  { headers: { Authorization: `Bearer ${key}` } }
);
const data = await res.json();
console.log(data.summary.referring_domains);

Python

import requests

domain = "example.com"
key = "crawly_live_your_key"

res = requests.get(
    "https://www.getcrawly.com/api/v1/domain-authority",
    params={"domain": domain},
    headers={"Authorization": f"Bearer {key}"},
)
data = res.json()
print(data["summary"]["referring_domains"])

Limits and errors

Rate limits

Requests per day	100
Reset	Every 24 hours
Burst	No hard limit

Error codes

400	Bad request
401	Invalid or missing key
429	Rate limit exceeded
500	Internal server error

Also available

Crawly MCP Server

Query your crawl data directly from Claude Code, Cursor, Codex or Windsurf using natural language. The MCP server connects your AI coding tool to Crawly's full crawl dataset.

Learn about the MCP server