Terms of Service (ToS)
The contract users accept to use your product: what they may do, what you owe them, and what happens when things go wrong.
See it
What it is
Where a privacy policy discloses, terms of service bind. It is the actual contract between you and every user: what they are allowed to do with the product, what you promise (deliberately very little), who owns what, and what happens when the relationship ends badly. Ten blocks cover most products: eligibility, account rules, acceptable use, fees and refunds, your IP and the license you grant users, the license users grant you over their content, termination and suspension, warranty disclaimers, a liability cap, and governing law plus dispute forum.
Reach for one the moment money, user-generated content, or an API is involved. The clauses that actually earn their keep are boring: the liability cap (usually fees paid in the last twelve months), the right to suspend an abusive account immediately, and the change-of-terms clause that says how you notify people when you edit it.
Gotcha: terms only bind if the user accepted them. A footer link and the hope that using the site counts (browsewrap) loses in court far more often than a checkbox next to 'I agree to the Terms' with a stored timestamp and version number (clickwrap). Second gotcha: copying a competitor's terms drags in their legal entity, their jurisdiction, and clauses about products you do not sell.
Ask AI for it
Draft terms of service for the product described below in plain English, numbered sections, short paragraphs, no Latin. Include: acceptance and who may use the service, account responsibilities, an acceptable use list with specific prohibited behaviors, fees, billing cycle, and refund policy, our IP and the limited license granted to users, the license users grant us over content they upload (limited to operating the service), third-party services, termination and suspension by either side, a warranty disclaimer, a limitation of liability capped at fees paid in the preceding twelve months, indemnification, how we notify users of changes and when changes take effect, governing law and forum, and a contact address. Add a plain-language one-sentence summary above each section. Flag anything jurisdiction-specific as a bracketed TODO for a lawyer rather than guessing.