OnTheMarket Real Time Datafeed (RTDF) API
OnTheMarket's member-only feed API for estate-agency CRM software. It is modelled on the Rightmove Real Time Datafeed (RTDF/ADF) specification, with OnTheMarket-specific differences in request and response fields and an "Only With Us" capability for exclusive listings; overseas properties are not supported. The service host realtime-api.onthemarket.com is live and presents an OnTheMarket TLS certificate (subject O=Agents' Mutual Limited, CN=*.onthemarket.com), and the enquiry endpoint /v1/property/getbranchemails is published in third-party CRM vendor setup instructions. OnTheMarket publishes no documentation, no OpenAPI, no Swagger and no OData $metadata for it: every path on the host returns HTTP 404 with an empty body to an anonymous client, and there is no self-service signup. Access requires an existing OnTheMarket agent membership with a data feed in place, arranged through OnTheMarket support — a Rightmove-style RTDF connection using a client certificate over TLS. Listed here as a real but undocumented and member-gated surface, with no machine-readable contract available to harvest.