MrKeyword Data API — SEO data for your own tool

For builders

What you can build.

Everything MrKeyword’s free tools and Domain Overview show is behind one key. Put your own name, design and pricing on it.

A keyword research tool

Volume, CPC, competition, difficulty and intent per keyword, related ideas, batch difficulty and clustering for lists of up to 500.

A domain or authority checker

Authority, referring domains, backlinks, traffic estimate, indexed pages and domain age — the complete overview in one call.

A backlink explorer

Page-level backlinks with anchors and follow status, referring domains strongest first, and what was gained or lost between web-graph releases.

Agency dashboards and AI agents

Score prospects, enrich a CRM, feed a Looker Studio report or give an AI agent real SEO numbers with sources and dates attached.

Step one

Get a key and make a call.

Create a free MrKeyword account, open Data API in the menu and press Create API key. The key starts with mkd_ and is shown once. Then:

A whole domain in one call

Authority, traffic, backlinks, pages, registration and hosting. Costs 3 credits.

curl "https://app.mrkeyword.io/api/v1/domains/overview?domain=example.com" \
  -H "Authorization: Bearer mkd_your_key"

Keyword metrics

Volume, CPC, competition, difficulty and intent for one keyword. 1 credit.

curl "https://app.mrkeyword.io/api/v1/keywords/metrics?keyword=plumber+near+me&market=US" \
  -H "Authorization: Bearer mkd_your_key"

Difficulty for a list

Up to 500 keywords per call, 1 credit per 10.

curl -X POST "https://app.mrkeyword.io/api/v1/keywords/difficulty" \
  -H "Authorization: Bearer mkd_your_key" \
  -H "content-type: application/json" \
  -d '{"keywords":["plumber near me","emergency plumber"],"market":"US"}'

The price list, as JSON

No key needed. The same table the meter charges from.

curl https://app.mrkeyword.io/api/v1/catalog

Send the key as Authorization: Bearer mkd_… or x-api-key: mkd_…. Keys belong on your server; revoke one from the same screen and it stops on the next call.

Reference

Endpoints and prices.

Every call is charged in credits; the number is printed on every response in meta.creditsCharged and the x-mrkeyword-credits-charged header. A call that fails on MrKeyword’s side is never charged.

The 16 endpoints of the Data API, base URL https://app.mrkeyword.io/api/v1.
Endpoint	What it returns	Credits
`GET /domains/overview` domain	Authority, traffic estimate, referring domains, backlinks and anchors, indexed pages, registration date and hosting in one call.	3
`GET\|POST /domains/authority` domain · { domains: [≤100] }	MrKeyword Link Authority 0–100, referring-domain and backlink totals, Common Crawl web-graph position.	1 per domain
`GET\|POST /domains/traffic` domain · { domains: [≤100] }	Estimated monthly organic clicks with a low–high band, the model and the reasoning.	1 per domain
`GET /domains/organic-keywords` domain, limit	Predicted organic keywords for any domain: keyword, position, ranking URL, volume, traffic, competitors.	3
`GET /domains/pages` domain, limit	The domain’s pages in the public index: URL, title, description, headings, word count.	1
`GET /domains/age` domain	Registration date, age, registrar, expiry and nameservers from the registry’s RDAP record, plus hosting IP and country.	1
`GET /domains/backlinks` domain, limit, offset	Page-level backlinks: source URL, target URL, anchor text, follow/nofollow, first and last seen.	2
`GET /domains/referring-domains` domain, limit	Referring domains with link counts, strongest first, and the domains gained or lost between Common Crawl releases.	2
`GET\|POST /keywords/metrics` keyword, market · { keywords: [≤100] }	Monthly search volume, CPC range, competition, difficulty and intent (US, CA, IN, GB, AU). A keyword MrKeyword has not stored yet is looked up live in Google Keyword Planner and saved; only keywords with data are charged.	1 per keyword with data
`GET /keywords/ideas` q, market, limit	Related keywords with the same metrics, biggest first. A new seed is expanded live in Google Keyword Planner and saved.	2 (free if none)
`POST /keywords/difficulty` { keywords: [≤500], market }	Keyword difficulty 0–100 for a list, from the stored row or the MrKeyword KD model.	1 per 10
`POST /keywords/intent` { keywords: [≤500] }	Informational, commercial, transactional or navigational, with the rule that matched.	1 per 10
`POST /keywords/cluster` { keywords: [≤500], threshold }	Topic clusters by semantic similarity.	1 per 10
`GET /serp/predicted` keyword, limit	A predicted results page from the public page index: domains, URLs, titles, ranked by relevance and authority.	2
`GET /usage`	Plan, credits used and left this month, pack balance, rate limit.	Free
`GET /catalog`	This list with plans and prices, no key needed.	Free

Pricing

Plans and credit packs.

A plan is a monthly credit allowance with a rate limit. A credit pack is 10,000 credits for $20, valid twelve months and spent only after the month’s allowance. API plans are separate from MrKeyword’s app plans: a free MrKeyword workspace can run API Growth.

Plan

Developer

Free

500 credits a month
60 calls a minute

No card. Enough to build and test.

Plan

API Starter

$29/month

20,000 credits a month
300 calls a minute

A small tool, a Chrome extension, an agency’s internal dashboards.

API Growth

$99/month

100,000 credits a month
600 calls a minute

A public keyword or domain checker with real traffic.

Plan

API Scale

$299/month

400,000 credits a month
1,500 calls a minute

Bigger volumes, or a data feed: contact us for more.

Buy from Data API inside MrKeyword (Stripe). Need millions of credits, an invoice, a reseller deal or a custom data feed? Contact us — credits can be granted to your workspace directly.

Behaviour

How answers look.

Shape: Every success is { data, meta }. meta carries the endpoint, the credits charged and remaining, your plan and the generation time. Batch endpoints answer one entry per input, so one bad domain or keyword never fails the whole call.
Honesty labels: Each figure says what it is — Measured, Derived, Estimated, Predicted or Not available — with a confidence, an asOf date, its source and the model where one applies. A domain MrKeyword has not seen answers with nulls and a reason, never an invented number.
Errors: 400 bad input (the message says what to fix) · 401 missing or revoked key · 402 not enough credits, with required and remaining · 429 over the plan’s rate limit, with Retry-After · 500 MrKeyword could not answer, not charged.
Rate limits: Per key: 60, 300, 600 or 1,500 calls a minute depending on the plan. Batch endpoints count as one call, so sending 100 domains at once is the cheap way through the limit.
CORS and keys: Responses allow any origin, but a key in a browser is visible to anyone who opens the page. Call the API from your server and put your own limits in front of your users.
Your usage: GET /usage is free and shows what is used and left; the Data API page in MrKeyword shows the same per key, per endpoint and per day, with the last 50 requests.

Where the data comes from

MrKeyword’s own index, nothing resold

You are buying data MrKeyword computes itself, so it can be sold on: no third-party SEO index sits behind any figure and nothing is scraped from Google.

Links and authority

MrKeyword’s crawler and global link index, merged with the Common Crawl web graph (tens of millions of domains). Authority is a documented PageRank on that graph; backlinks are the links actually found.

Traffic and keywords

Traffic is a published model over the domain’s web-graph position, calibrated by connected sites’ real Search Console clicks. Keyword volumes are Google Keyword Planner numbers stored in MrKeyword’s keyword database; difficulty and intent are MrKeyword’s own models.

Pages and predicted rankings

The public page index holds titles, descriptions, headings and word counts of public pages from MrKeyword’s crawler and Common Crawl. Predicted SERPs and organic keywords rank those pages against each other, and say Predicted.

Registration and hosting

Domain age comes from the registry’s own RDAP record via the IANA bootstrap; hosting IP and country from DNS. Both are read live and cached briefly.

Get a key and make the first call.

Create a free account, open Data API, press Create API key. 500 credits a month to build with, no credit card.

Get started free No credit card required.

Build your own SEO tool on MrKeyword’s data.

What you can build.

A keyword research tool

A domain or authority checker

A backlink explorer

Agency dashboards and AI agents

Get a key and make a call.

A whole domain in one call

Keyword metrics

Difficulty for a list

The price list, as JSON

Endpoints and prices.

Plans and credit packs.

Developer

API Starter

API Growth

API Scale

How answers look.

Links and authority

Traffic and keywords

Pages and predicted rankings

Registration and hosting

Get a key and make the first call.