Mephistopheles is a fact-checking service — it checks text you give it against independent sources. Our value is the checking, not collecting your data. This covers the website (mephistopheles.ai) and the browser extension.
When you verify an answer, paste text, or upload a document, that content is sent to our servers and used only to produce the result — we extract the factual claims and check each against independent sources (web search, Wikipedia, Wikidata) and an AI judge. We do not retain the content of what you check. Document jobs are held only long enough to return your result (a few minutes) and then dropped; text checks are transient. We log only anonymized usage — which feature was used, a hashed identifier, and a timestamp — never the content itself.
De-identification: documents you check with the drag-and-drop tool are de-identified on our own infrastructure (names, dates, IDs and other identifiers stripped) before any external check. Text you check via the extension, paste, or chat is sent to be checked as written — so please don't paste secrets you wouldn't want processed by a third-party AI.
If you sign in, we store your email (for passwordless magic-link login), a generated API key, and your plan. Payments are handled by Stripe — we never see or store your card number, only Stripe's tokens.
If you connect your own OpenRouter key, it stays in your browser, is used only to make your requests, and is never stored on our servers.
The extension sends only the text you choose to verify to our verification endpoint. If you sign in, your key is kept in your browser's extension storage. It collects nothing else, and does not read pages or content you haven't asked it to check.
We use IP addresses for rate-limiting and abuse prevention, and to count anonymous usage. If you log in we set a single session cookie. No advertising or cross-site tracking cookies.
To provide the service we use: independent search sources and an AI model provider for the judging step (document content is de-identified first); Stripe for payments; and an email provider for login links. We do not sell your personal data.
Account data is kept while your account is active — email us to delete it. Verification content is not retained. Anonymized usage counts are kept for product analytics.
Questions or deletion requests: [email protected].
Mephistopheles flags likely errors for you to review; it is not legal, medical, or financial advice. ← Home