Privacy Policy

We collect different data depending on how you use the Service:

• Usage analytics. Aggregate, non-identifying data about which pages and calculators are used, how often, and general traffic patterns — used to understand which tools are useful and to spot errors.
• Calculator inputs. Values you enter into a web calculator or send to an API endpoint (e.g. a mortgage amount, a date range) are processed to compute a result and are not stored beyond what's needed to serve that response, except where caching is used to speed up repeated requests for the same public reference data (e.g. exchange rates, country statistics) — never your specific inputs.
• Account and API key data. If you create an account, we store your email address, a hashed representation of your API key(s), your selected plan, and your API call usage counts, so we can authenticate requests and enforce plan limits.
• Payment information. If you subscribe to a paid plan, payment is handled entirely by Stripe. We never receive or store your card number, expiry date, or CVC — Stripe provides us with a customer and subscription ID only.
• Technical data. Standard request metadata (IP address, user agent, timestamp) is logged short-term for rate limiting, abuse prevention, and debugging.

Data collected is used to:

• Operate and maintain the web calculators, REST API, and MCP server
• Authenticate API requests and enforce per-plan rate limits
• Process payments and manage subscriptions via Stripe
• Respond to support requests
• Monitor for abuse, fraud, and service errors
• Understand aggregate usage patterns to improve existing tools and prioritize new ones

We do not sell your personal data to third parties.

The web calculators use a minimal set of cookies and similar technologies required for the site to function (e.g. remembering a signed-in session) and, where enabled, to serve advertising.

We use Google AdSense to display ads on some pages. Google and its partners may use cookies and similar technologies to serve ads based on your visits to this and other websites. You can opt out of personalized advertising by visiting Google Ads Settings, or generally at aboutads.info. For details on how Google uses data when you use our site, see how Google uses information from sites that use its services.

We rely on the following third-party services to operate the Service. Each processes data under its own privacy policy:

• Stripe — payment processing, subscription billing, and storage of payment methods.
• Railway — hosting for the REST API and MCP server.
• Vercel — hosting and content delivery for the web calculators.
• Upstash (Redis) — short-lived caching of API responses and rate-limit counters.
• Google AdSense — advertising, as described above.

Depending on where you live, you may have the right to access, correct, export, or delete the personal data we hold about you, and to object to or restrict certain processing. This includes rights under the EU/UK General Data Protection Regulation (GDPR) and the California Consumer Privacy Act (CCPA).

To exercise any of these rights, contact us at support@stupidlyclever.com. We will respond within the timeframe required by applicable law. If you are not satisfied with our response, you have the right to lodge a complaint with your local data protection authority.

Account and API key data is retained for as long as your account is active, plus a reasonable period afterward for legal, tax, and fraud-prevention purposes. Request logs used for rate limiting and abuse prevention are retained for a limited period (typically 30 days) and then deleted. Calculator inputs submitted to a stateless endpoint are not retained beyond generating the response, except where noted in Section 1.

You may request deletion of your account and associated personal data at any time by contacting support@stupidlyclever.com.

API keys are stored hashed, not in plaintext. Traffic to the web calculators, REST API, and MCP server is encrypted in transit via HTTPS/TLS. No method of transmission or storage is 100% secure, but we take reasonable technical and organizational measures to protect your data.

The Service is not directed at children under 16, and we do not knowingly collect personal data from them. If you believe a child has provided us with personal data, contact us and we will delete it.

We may update this policy from time to time. Material changes will be reflected by updating the "Last updated" date above. Continued use of the Service after a change constitutes acceptance of the revised policy.

Questions about this policy or how your data is handled can be sent to support@stupidlyclever.com. See also our Terms of Service.