---
title: "Fact lag (fl1): every change the business made to its published name, phone or address, with the day each verified crawler first fetched the home page afterwards and the days until each engine stated the new value (or that it still states the old one); plus today's answers per engine, a wrong value traced to where it comes from, this site's own past values included. Owner data: panel, internal key or a licence covering the domain"
method: GET
path: "/api/fact-lag"
---

# Fact lag (fl1): every change the business made to its published name, phone or address, with the day each verified crawler first fetched the home page afterwards and the days until each engine stated the new value (or that it still states the old one); plus today's answers per engine, a wrong value traced to where it comes from, this site's own past values included. Owner data: panel, internal key or a licence covering the domain

`GET /api/fact-lag`

## Request

- Base URL: `https://crawlcheck.io`
- URL: `https://crawlcheck.io/api/fact-lag`
- Auth: none required

## Query parameters

- `domain` string, required

## Response `200`

crawlcheck-fact-lag

- object, nullable
  - `kind` string, nullable
  - `v` number, nullable
  - `generated_at` string, nullable
  - `domain` string, nullable
  - `facts` object[], nullable
    - `fact` string, nullable
    - `value` string, nullable
    - `since` string, nullable
    - `scans_seen` number, nullable
    - `previous` object[], nullable
      - `value` string, nullable
      - `from` string, nullable
      - `until` string, nullable
  - `changes` object[], nullable
    - `fact` string, nullable
    - `old_value` string, nullable
    - `new_value` string, nullable
    - `last_seen_old` string, nullable
    - `first_seen_new` string, nullable
    - `crawlers` object, nullable
      - `Googlebot` object, nullable
        - `first_verified_fetch` string, nullable
        - `days_after_change` number, nullable
      - `GPTBot` object, nullable
        - `first_verified_fetch` string, nullable
        - `days_after_change` number, nullable
    - `crawlers_measured` boolean, nullable
    - `engines` object, nullable
      - `Gemini with Google Search` object, nullable
        - `state` string, nullable
        - `first_correct` string, nullable
        - `lag_days` number, nullable
      - `gpt-oss-120b (no search)` object, nullable
        - `state` string, nullable
        - `last_reading` string, nullable
        - `last_result` string, nullable
        - `stated` string[], nullable
        - `days_so_far` number, nullable
  - `current` object[], nullable
    - `engine` string, nullable
    - `read_at` string, nullable
    - `state` string, nullable
    - `phone` object, nullable
      - `result` string, nullable
      - `stated` string[], nullable
      - `printed_by` object, nullable
        - `(303) 555-0142` string[], nullable
    - `address` object, nullable
      - `result` string, nullable
    - `hours` string, nullable
  - `reading` string, nullable
  - `sources` object, nullable
    - `facts` string, nullable
    - `crawlers` string, nullable
    - `engines` string, nullable

## Other responses

- `404`: not yours to read

---

[API](https://skmtc.dev/crawlcheck/apis/crawlcheck-api.md) · [All operations](https://skmtc.dev/crawlcheck/apis/crawlcheck-api/llms.txt) · [OpenAPI document](https://skmtc.dev/crawlcheck/apis/crawlcheck-api/revisions/57acbd6d4489?raw)