Privacy policy

Effective 2026-10-14.

OPC Studio is a desktop app that runs on your computer. It has no account and no telemetry, and the project runs no server that the app talks to. We don’t collect, store, sell or share any personal information.

This policy is published at https://opcstudio.nilpointer.tech/privacy/.

What stays on your computer

• Servers: the servers you save, including names, sites, colors, endpoint URLs, security settings, safety settings and, for a user certificate, the paths of its files, are stored in one file, workspace.json, in your operating system’s per-user configuration folder, next to a small settings.json with the app’s own settings (the theme, panel sizes and the recent watch-list files). A saved server never holds a password. A file that cannot be read is kept aside next to it, and the app opens empty.
• Passwords and key passphrases: a user name’s password and a key passphrase go to your system’s credential store (Windows Credential Manager, macOS Keychain, or Secret Service on Linux), or to an encrypted file in the configuration folder where there is none. They are never written to workspace.json, to exports, or to the app’s own state. A password is sent only to the OPC UA server you set it up for, and only encrypted with that server’s certificate: a password that would travel in clear is refused. A passphrase never leaves your computer. Deleting a server deletes its secrets.
• Certificates and the trust list: the app keeps its own certificate and private key, the certificates you trusted and the ones you rejected in a pki folder in your per-user data folder, in the usual layout: own, trusted, rejected and issuers, with crl folders for revocation lists. You can read, copy and delete these files by hand. The private key file is readable only by you on Linux and macOS. The certificate is created on first start, and never sent anywhere except to the OPC UA servers you connect to, as part of the connection.
• Your servers: the app talks only to the OPC UA servers you set up and to its built-in simulator if you start it. Beyond browsing, reading and receiving the values you subscribed to, it sends something to a server only when you ask it to: writing a value, calling a method, acknowledging an alarm, reading history or testing a connection.
• Trace, recordings and files: the trace of service calls is kept in memory while a server is connected, and the app writes recordings to a recordings folder in your per-user data folder, and can write CSV exports, watch lists, exported server lists and your exported certificate to a place you choose. They stay on your computer and are never sent anywhere.
• Crash reports and logs: if the app crashes it writes a crash report to a crash folder, and it keeps a log of its warnings in a logs folder, both in your per-user data folder; they stay on your computer and nothing is sent anywhere.
• Import and export: an exported server list contains no passwords. An imported server that has a user name asks for its password the first time you connect.

This website

The website at opcstudio.nilpointer.tech is hosted on Cloudflare. It sets no cookies and runs no analytics or tracking scripts. As with any web host, Cloudflare handles the technical connection data needed to serve pages and downloads, under its own privacy policy.

Contact

Questions about privacy: email edneyphp@gmail.com.