Website Data API: What It Returns and How to Use It

A website data API takes a domain and returns facts about that site as structured data instead of a web page for a human to read. The useful ones answer narrow, checkable questions: does robots.txt let AI crawlers in, does the site publish an llms.txt file, are SPF, DKIM and DMARC records set up, does a page expose tools to browser agents. You send example.com, you get a verdict you can store, diff and alert on.

That is different from a scraping API, which hands you raw HTML, and from a traffic-estimate API, which guesses at visits. A checks API does the fetching, DNS lookups and interpretation for you, and charges per call. The trade-off is scope: you get the checks the vendor built, not arbitrary page extraction.

One concrete example is BusinessMCP’s website checks API. It exposes four per-domain endpoints under a single bearer token: an AI readiness grade at $0.03 per call, and AI crawler access, WebMCP detection and email authentication at $0.01 each. Each endpoint has a REST route and an MCP tool of the same name, so a script and an AI agent can use the same service. The wider BusinessMCP data API catalogue also covers company, IP, people and trust lookups, which are a different job. New accounts get $5 of credit for 7 days, so you can test the checks on your own domains before paying anything. If you want to try one without code first, the free AI readiness grader runs the same scoring check in a browser form.

This publication is organised by the decisions you actually face when adopting one.

• Is an API the right tool at all? Start with what a website data API is and the comparison with DIY scraping.
• What will it cost? Work through the per-call pricing maths before you commit to a monthly audit schedule.
• How do I call it? See the Python example and the notes on using it from an AI agent.
• What do the individual checks mean? Read about AI readiness scores, AI crawler access in robots.txt, llms.txt, WebMCP and email authentication.
• How do I run it at scale? Try bulk domain audits and scheduled monitoring.

Two cautions apply to every service of this type. First, a check measures what a machine can read today, not what any AI product will do with it; a clean score does not mean assistants will cite you. Second, an inconclusive result is data too: when a DNS lookup does not complete or a robots.txt file cannot be read, a good API says unknown rather than guessing allowed or failed. Build your code to keep that third state.

We are an independent publication. We name the products we discuss, say what they do and where they stop, and link to primary pages so you can verify. Prices and features change, so confirm on the vendor’s page before you budget.