🤵 Privacy

Data Butler (databutler.dev) serves verified reference data to AI agents over REST and MCP. This page says plainly what we record when you — or an agent acting for you — use it. The short version: no accounts, no cookies, no stored IP addresses, no logged request bodies.

What we record

No accounts. There is nothing to sign up for or log in to; no API keys.
No cookies and no browser storage. Pages are static; nothing identifies a returning visitor.
Anonymous event counts. Each API or MCP call sends one event to Google Analytics 4 via its server-side Measurement Protocol. An event carries the event name (e.g. agent_mcp_uk_rates_lookup, cite_page_view), a client class derived from the User-Agent header (e.g. claude, cursor, python, browser), the first 100 characters of that User-Agent string, and a random per-request identifier that is never reused. No query parameters, tool arguments, IP address or page URL are included.
No IP addresses stored by us. We do not keep server logs. Our hosting provider (Vercel) handles requests and may keep short-lived operational logs under its own privacy policy; we do not export or retain them.
No request bodies logged. The question an agent asks (a tax category, a domain, a dataset of numbers for a statistics tool, a vehicle) is processed to answer it and then discarded.

Third-party fetches made on your behalf

Some tools compute their answer live by fetching public sources. In those cases the value you asked about travels to that source, together with our User-Agent (databutler.dev-provenance/1.0 or databutler-hub/1.0); your IP address does not, because the request originates from our server.

Tool	Source contacted	What it receives
`domain_provenance`	RDAP via `rdap.org` and the TLD's registry	the domain name you asked about
`package_provenance`	`registry.npmjs.org` / `pypi.org`	the package name you asked about
`uk_mot_reliability`, `uk_mot_vehicle_search`	`whatbreaks.uk` (same operator; see its own /api)	make, model, year, mileage or search text
`take_home_pay`	the `lifebynumbers.net` calculation backend (same operator, an AWS Lambda; see its privacy policy)	country, gross salary and the optional state / province / region / filing status — no name or identifier
weekly source watcher (not user-triggered)	`www.gov.uk` content API and exam-board pages	nothing about any user — it re-checks our own source URLs

Everything else (UK rates, exams, statistics, French and Japanese recall datasets) is answered from data on our server with no external call.

Citation pages

Every answer carries a cite.url permalink such as /r/uk/rates?category=income-tax. These pages are stateless: the URL encodes the query and re-runs it. Opening one records a single anonymous cite_page_view event as above. They are marked noindex.

Contact

Questions or requests: open an issue on the project repository, github.com/physics-star-cat/databutler. This is the same route used for the data-source change notices the project files for itself.

Last updated 2026-10-03. Data Butler is operated by the same individual as whatbreaks.uk, lowriskquotes.com and lifebynumbers.net. databutler.dev · /api · llms.txt