Private AI Glossary

Short, plain-English definitions of the terms that come up when people talk about private AI chat — the browser tech that keeps your history on your own device, and the provider-side terms that decide whether your conversations are stored, trained on, or covered by a compliance contract. Each links to a fuller explainer.

Terms

OPFS (Origin Private File System)
A sandboxed, origin-scoped file system built into modern browsers that lets a web app store files privately on your own device, isolated from other sites and from your regular files.
Zero-Retention API
An AI provider API mode in which your prompts and outputs are not persisted after the response is returned — nothing is kept server-side to log, review, or breach.
BAA (Business Associate Agreement)
A HIPAA contract that makes a vendor handling protected health information legally accountable for safeguarding it. Consumer AI plans do not sign one.
Training Opt-Out
A setting or contractual term that excludes your conversations from being used to train or fine-tune an AI provider’s models.

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