Accounts
- Passwords are hashed with scrypt (n=2^14, per-user salt). We cannot read them.
- Sessions are HMAC-SHA256 signed cookies — a restart does not log you out, and a forged cookie is rejected.
- Plan state is read from the database on every request, so a lapsed or disabled account loses paid access immediately, not when a cookie expires.
Your files
- DXF, OBJ, PDF, XLSX and JSON are generated per request and sent to you. We do not keep a copy; the account stores the parameters that produced them.
- Downloads are signed and expire in an hour; each export is stamped with the licence and logged, so a leaked drawing is traceable to the account that made it.
- Free previews are deliberately rounded, undimensioned and watermarked — not fabrication files.
Payments
Card details go directly to Stripe; we never see or store a card number, and only receive the outcome, amount and a customer reference. PayPal payments are the same story on their side. Both are audited by their own compliance programmes, not by us.
Transport and hosting
HTTPS everywhere, terminated at Cloudflare and again at Railway; the application and its SQLite database run on a Railway volume in the United States. The admin area is restricted to the owner account and every action is logged.
Backups
The owner can download a consistent database dump from the admin area at any time. Off-site copies are being added; until they exist, that dump is the backup.
Reporting a problem
Email [email protected]. We answer within two business days, and a vulnerability report gets a reply the same day where we can.
What we do not run
No third-party analytics, no advertising pixels, no session recording, no fonts fetched from a third party.