API

On the Pro and API plans. A workspace owner or admin makes a key in the app. Send it with every request:

Authorization: Bearer kl_...

One domain

GET /v1/domains/example.com?referrers=25

Up to 100 domains

POST /v1/domains/bulk
{ "domains": ["example.com", "example.org"], "referrers": 5 }

Keyword difficulty

Up to 50 keywords. List the sites at the top of the results, best first; the first 10 count.

POST /v1/keywords/difficulty
{ "keywords": [{ "keyword": "cloud hosting", "ranking_domains": ["a.com", "b.com"] }] }

Your usage

GET /v1/usage

What comes back

Every number says where it came from and whether it was measured or modeled:

{ "value": 90, "source": "common_crawl", "label": "modeled", "observed_at": "2026-11-04T03:30:22Z", "scale": "0-100" }

Limits and errors

At most 120 requests a minute per key. Errors look like { "error": { "code", "message" } }.

• 401 the key is missing or wrong
• 402 your plan doesn't include this
• 429 over your monthly limit or the rate limit
• 503 the data isn't reachable just now; nothing was counted