{
  "title":"Public Hidden-Fee Taxonomy",
  "version":"0.1",
  "status":"reference framework; not a prevalence dataset",
  "suggested_citation":"DetectHiddenFees Editorial Team. Public Hidden-Fee Taxonomy, version 0.1, July 31, 2026.",
  "categories":[
    {"id":"mandatory-disclosed","label":"Disclosed mandatory fee","definition":"A required charge identified before commitment or payment.","alternate_names":["regulatory fee","service fee"],"industries":["telecom","travel","utilities"],"locations":["price summary","contract","invoice"],"legitimate_uses":["cost recovery","regulated charges","service administration"],"warning_signs":["appears late","base price excludes material required amount"],"questions":["Is it mandatory?","When was it disclosed?"],"limitations":"Disclosure quality and legal treatment depend on jurisdiction and transaction context."},
    {"id":"poorly-disclosed-mandatory","label":"Poorly disclosed mandatory fee","definition":"A required charge whose timing, label, amount, or condition is difficult to understand before commitment.","alternate_names":["late-disclosed fee","unitemized required charge"],"industries":["ticketing","travel","services","housing"],"locations":["checkout","terms","invoice"],"legitimate_uses":["may reflect a real cost, even when presentation is unclear"],"warning_signs":["vague label","late addition","no total price"],"questions":["What does it cover?","Could the advertised total include it?"],"limitations":"A presentation concern is not by itself a legal conclusion."},
    {"id":"optional-add-on","label":"Optional add-on","definition":"A charge for an optional product or service that should be distinguishable from the required purchase.","alternate_names":["upgrade","protection plan","premium add-on"],"industries":["travel","auto","software","telecom"],"locations":["checkout","quote","order form"],"legitimate_uses":["additional service or convenience"],"warning_signs":["preselected option","unclear opt-out"],"questions":["Can I decline it?","What value does it provide?"],"limitations":"Selection and disclosure rules vary."},
    {"id":"automatically-selected","label":"Automatically selected add-on","definition":"An optional charge selected by default unless the consumer changes the selection.","alternate_names":["prechecked add-on","default upgrade"],"industries":["travel","ticketing","subscriptions"],"locations":["checkout","order summary"],"legitimate_uses":["interface convenience, subject to applicable requirements"],"warning_signs":["selection is easy to miss","total changes late"],"questions":["Was it selected by me?","How do I remove it?"],"limitations":"The interface, jurisdiction, and transaction matter."},
    {"id":"recurring","label":"Recurring fee","definition":"A charge that repeats while an account, subscription, or service remains active.","alternate_names":["monthly fee","maintenance fee","membership fee"],"industries":["subscriptions","banking","telecom"],"locations":["terms","billing schedule","statement"],"legitimate_uses":["ongoing service or account maintenance"],"warning_signs":["renewal language","unclear cancellation"],"questions":["How often is it charged?","How is it canceled?"],"limitations":"Account history and renewal terms are necessary."},
    {"id":"contract-triggered","label":"Contract-triggered fee","definition":"A charge activated by a contract event such as cancellation, renewal, late payment, or exceeding a limit.","alternate_names":["termination fee","late fee","renewal charge"],"industries":["leases","services","software","financing"],"locations":["termination clause","fee schedule","payment terms"],"legitimate_uses":["recovering committed costs or administering a contract"],"warning_signs":["unclear trigger","undefined calculation","short notice window"],"questions":["What triggers it?","How is it calculated?"],"limitations":"Interpretation and enforceability require context and may require professional review."},
    {"id":"duplicate-or-unclear","label":"Duplicate or unclear charge","definition":"A repeated, bundled, or insufficiently described line item that requires reconciliation.","alternate_names":["miscellaneous charge","adjustment","other fee"],"industries":["all billing contexts"],"locations":["invoice","statement","estimate"],"legitimate_uses":["may reflect a correction or bundled service"],"warning_signs":["same amount twice","no itemization","quote mismatch"],"questions":["Can the provider itemize it?","Does another line already cover it?"],"limitations":"Complete records and human confirmation are required."}
  ],
  "methodology":"Categories organize educational content and future research. They do not establish illegality, deception, prevalence, or consumer entitlement. Entries should be reviewed against the current document, source, industry, and jurisdiction.",
  "revision_history":[{"date":"2026-07-31","change":"Initial public reference framework derived from Phase 3 taxonomy governance."}]
}