CrawlCheck Fact Lag API
The Fact Lag API from CrawlCheck — 1 operation(s) for fact lag.
Work with this as data
Every API here is available over the APIs.io API and to AI agents over MCP.
MCP server
One button, every client — Claude, Cursor, VS Code and the rest.
https://apis.io/mcp
Tools for apis
7 MCP tools reach this
find_apisBrowse and filter every API in the catalog.get_api_artifactsOne API's artifacts, grouped by type.get_openapiThe primary OpenAPI for this API.find_similar_apisAPIs that look like this one.apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.resolveTurn a domain, URL or GitHub org into the provider it belongs to.find_cohortsEvery scored population of providers in the catalog.
Call it yourself
curl for this page
This API
curl "https://apis.io/api/v1/apis/crawlcheck-io:crawlcheck-io-fact-lag-api"
All apis
curl "https://apis.io/api/v1/apis?limit=25"Calls without X-API-Key need no key. Calls with it need a paid plan — get a key.
Get an API key
Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.
A second provider on the same verified email joins the account you already have.
OpenAPI Specification
openapi: 3.2.0
info:
title: Crawlcheck Io Fact Lag API
version: '1'
contact:
name: CrawlCheck
url: https://crawlcheck.io/policy
email: hello@crawlcheck.io
license:
name: Terms
url: https://crawlcheck.io/policy
x-core-contract:
promise: 'These operations are the core contract. They stay at /api/v1 and keep answering for at least 180 days after any /api/v2 is announced; their stable fields change only in a new major version, and their provisional fields only after 30 days'' notice, per /docs/api/compatibility. Verifying what they return needs none of these calls: crawlcheck-verify.mjs checks a document on your machine against the published keys (/.well-known/http-message-signatures-directory) and the rotation record, read once with --online or saved for --keys. Everything else documented here is useful but secondary, and may change with the notice its fields'' tags promise.'
operations:
- method: GET
path: /api/v1/resolve
operationId: resolveDomainV1
- method: POST
path: /api/v1/resolve
operationId: resolveBatchV1
- method: POST
path: /api/v1/preflight
operationId: preflightV1
- method: GET
path: /api/v1/decisions/{sha256}
operationId: decisionCheckV1
- method: GET
path: /api/v1/revocations
operationId: revocations
- method: GET
path: /api/v1/visitor
operationId: visitorResolveV1
- method: POST
path: /api/v1/visitor
operationId: visitorResolveBatchV1
- method: GET
path: /api/v1/mcp/scan
operationId: mcpScanUrl
- method: POST
path: /api/v1/mcp/lock/check
operationId: mcpLockCheck
list: https://crawlcheck.io/api/v1/core
description: 'Operations tagged Fact Lag across 2 of this provider''s published API definitions: crawlcheck-io-openapi.json, crawlcheck-io-openapi.yml. Each path carries the servers of the definition it was published in.'
servers:
- url: https://crawlcheck.io
tags:
- name: Fact Lag
paths:
/api/fact-lag:
get:
operationId: factLag
summary: 'Fact lag (fl1): every change the business made to its published name, phone or…'
parameters:
- name: domain
in: query
required: true
schema:
type: string
responses:
'200':
description: crawlcheck-fact-lag
content:
application/json:
examples:
worked:
summary: Shape from the build harness on 2026-10-15; owner data, so the example is illustrative.
value:
kind: crawlcheck-fact-lag
v: 1
generated_at: '2026-10-15T23:40:00.000Z'
domain: example.com
facts:
- fact: phone:schema
value: '3035550188'
since: '2026-09-20T10:00:00.000Z'
scans_seen: 24
previous:
- value: '3035550142'
from: '2026-08-01T10:00:00.000Z'
until: '2026-09-19T10:00:00.000Z'
changes:
- fact: phone:schema
old_value: '3035550142'
new_value: '3035550188'
last_seen_old: '2026-09-19T10:00:00.000Z'
first_seen_new: '2026-09-20T10:00:00.000Z'
crawlers:
Googlebot:
first_verified_fetch: '2026-09-21'
days_after_change: 1
GPTBot:
first_verified_fetch: '2026-10-02'
days_after_change: 12
crawlers_measured: true
engines:
Gemini with Google Search:
state: caught_up
first_correct: '2026-09-24T09:17:00.000Z'
lag_days: 4
gpt-oss-120b (no search):
state: states_old_value
last_reading: '2026-10-15T09:17:00.000Z'
last_result: wrong
stated:
- (303) 555-0142
days_so_far: 25.6
current:
- engine: gpt-oss-120b (no search)
read_at: '2026-10-15T09:17:00.000Z'
state: answered
phone:
result: wrong
stated:
- (303) 555-0142
printed_by:
(303) 555-0142:
- this site itself, until 2026-09-19
- yelp.com
address:
result: city_only
hours: not_stated
reading: '1 published fact change(s). For each: the day each verified crawler first fetched the home page after it, and the days until each engine stated the new value.'
sources:
facts: the site's own pages and structured data, every scan
crawlers: the site's edge log, verified against operators' published ranges
engines: one customer question a day per engine (https://crawlcheck.io/api/v1/business/ai-answers?domain=example.com)
schema:
type:
- object
- 'null'
properties:
kind:
type:
- string
- 'null'
v:
type:
- number
- 'null'
generated_at:
type:
- string
- 'null'
domain:
type:
- string
- 'null'
facts:
type:
- array
- 'null'
items:
type:
- object
- 'null'
properties:
fact:
type:
- string
- 'null'
value:
type:
- string
- 'null'
since:
type:
- string
- 'null'
scans_seen:
type:
- number
- 'null'
previous:
type:
- array
- 'null'
items:
type:
- object
- 'null'
properties:
value:
type:
- string
- 'null'
from:
type:
- string
- 'null'
until:
type:
- string
- 'null'
additionalProperties: true
additionalProperties: true
changes:
type:
- array
- 'null'
items:
type:
- object
- 'null'
properties:
fact:
type:
- string
- 'null'
old_value:
type:
- string
- 'null'
new_value:
type:
- string
- 'null'
last_seen_old:
type:
- string
- 'null'
first_seen_new:
type:
- string
- 'null'
crawlers:
type:
- object
- 'null'
properties:
Googlebot:
type:
- object
- 'null'
properties:
first_verified_fetch:
type:
- string
- 'null'
days_after_change:
type:
- number
- 'null'
additionalProperties: true
GPTBot:
type:
- object
- 'null'
properties:
first_verified_fetch:
type:
- string
- 'null'
days_after_change:
type:
- number
- 'null'
additionalProperties: true
additionalProperties: true
crawlers_measured:
type:
- boolean
- 'null'
engines:
type:
- object
- 'null'
properties:
Gemini with Google Search:
type:
- object
- 'null'
properties:
state:
type:
- string
- 'null'
first_correct:
type:
- string
- 'null'
lag_days:
type:
- number
- 'null'
additionalProperties: true
gpt-oss-120b (no search):
type:
- object
- 'null'
properties:
state:
type:
- string
- 'null'
last_reading:
type:
- string
- 'null'
last_result:
type:
- string
- 'null'
stated:
type:
- array
- 'null'
items:
type:
- string
- 'null'
days_so_far:
type:
- number
- 'null'
additionalProperties: true
additionalProperties: true
additionalProperties: true
current:
type:
- array
- 'null'
items:
type:
- object
- 'null'
properties:
engine:
type:
- string
- 'null'
read_at:
type:
- string
- 'null'
state:
type:
- string
- 'null'
phone:
type:
- object
- 'null'
properties:
result:
type:
- string
- 'null'
stated:
type:
- array
- 'null'
items:
type:
- string
- 'null'
printed_by:
type:
- object
- 'null'
properties:
(303) 555-0142:
type:
- array
- 'null'
items:
type:
- string
- 'null'
additionalProperties: true
additionalProperties: true
address:
type:
- object
- 'null'
properties:
result:
type:
- string
- 'null'
additionalProperties: true
hours:
type:
- string
- 'null'
additionalProperties: true
reading:
type:
- string
- 'null'
sources:
type:
- object
- 'null'
properties:
facts:
type:
- string
- 'null'
crawlers:
type:
- string
- 'null'
engines:
type:
- string
- 'null'
additionalProperties: true
additionalProperties: true
x-schema-source: worked-example
'404':
description: not yours to read
x-codeSamples:
- lang: Shell
label: curl
source: 'curl -s -H ''x-crawlcheck-key: cc_…'' ''https://crawlcheck.io/api/fact-lag?domain=example.com'''
security: []
x-auth: public; no credential read
tags:
- Fact Lag
servers:
- url: https://crawlcheck.io
components:
securitySchemes:
licenceKey:
type: apiKey
in: header
name: x-crawlcheck-key
description: 'Your licence key: cc_ followed by 32 hex characters. Sent on every keyed call.'
bearer:
type: http
scheme: bearer
description: The same licence key as a Bearer token. Accepted on /api/v1/* and /api/usage.
externalDocs:
url: https://crawlcheck.io/docs/api
description: Human-readable reference
x-refined-from:
- crawlcheck-io-openapi.json
- crawlcheck-io-openapi.yml