# OnTheMarket

> OnTheMarket is the third-largest residential property portal in the United Kingdom, operating onthemarket.com. Founded in 2013 by Agents' Mutual Limited as an agent-owned challenger to Rightmove and Zoopla, it was acquired by CoStar Group in December 2023. OnTheMarket publishes NO public API, NO developer portal and NO machine-readable contract of any kind. Its only API-shaped product is the member-only OnTheMarket Real Time Datafeed (RTDF), reachable at realtime-api.onthemarket.com by estate-agency CRM vendors that hold an OnTheMarket data-feed agreement. This file is generated by API Evangelist from the catalog record; it is not published by OnTheMarket.

## Access

- Access model: paid, membership-required, no self-service signup, no free trial, not public.
- To integrate you must be (or act for) an OnTheMarket member estate agent, homebuilder or developer with a listing agreement. Feeds are arranged through OnTheMarket support, not through a developer programme.
- Authentication is not published. Consistent with the Rightmove RTDF lineage the connection is understood to be mutual TLS with a client certificate; this is inferred from third-party CRM integration notes, not from an OnTheMarket document.
- OnTheMarket's Terms of Use clause 3.3 prohibits automated access to any page of the site other than the home page unless the program identifies itself uniquely and honours robots.txt.

## APIs

- [OnTheMarket Real Time Datafeed (RTDF) API](https://expert.onthemarket.com/contact-us/): Member-only feed API for estate-agency CRM software, modelled on the Rightmove Real Time Datafeed (RTDF/ADF) specification with OnTheMarket-specific fields and an "Only With Us" exclusive-listing capability. Base URL https://realtime-api.onthemarket.com/v1. Live host, but every path returns HTTP 404 with an empty body to an anonymous caller. No OpenAPI, Swagger, WSDL, GraphQL schema, AsyncAPI or OData $metadata is published anywhere.

## What does not exist

- No developer portal, documentation site, API reference or getting-started guide. developer., developers., api., docs., partner., partners., feeds., datafeed., data. and integrations.onthemarket.com do not resolve.
- No OpenAPI or Swagger. /openapi.json, /openapi.yaml, /swagger.json, /api-docs, /docs and /redoc return 404 on both www.onthemarket.com and realtime-api.onthemarket.com.
- No GraphQL endpoint, no AsyncAPI document, no webhooks (RTDF enquiry delivery is pull-based), no event stream.
- No official SDKs, no CLI, no Postman collection, no sandbox, no changelog, no status page and no published rate limits.
- No OIDC discovery document, no OAuth metadata, no security.txt, no api-catalog — see well-known/onthemarket-well-known.yml for the full probe record.
- No RESO Web API or Data Dictionary certification, no OData service, no Universal Property Identifier. RESO is a North American construct; the UK has no MLS and no certification layer for listing data.
- No open data. The genuinely open UK property layer belongs to HM Land Registry (Price Paid Data) and Ordnance Survey, not to the portals.

## Catalog artifacts

- [apis.yml](https://raw.githubusercontent.com/api-evangelist/onthemarket/refs/heads/main/apis.yml): APIs.json catalog record.
- [review.yml](https://raw.githubusercontent.com/api-evangelist/onthemarket/refs/heads/main/review.yml): Full API Evangelist review, including every probe and its HTTP status.
- [well-known/onthemarket-well-known.yml](https://raw.githubusercontent.com/api-evangelist/onthemarket/refs/heads/main/well-known/onthemarket-well-known.yml): /.well-known/ probe record (all negative).
- [security/onthemarket-domain-security.yml](https://raw.githubusercontent.com/api-evangelist/onthemarket/refs/heads/main/security/onthemarket-domain-security.yml): TLS/HSTS/DNSSEC/CAA/SPF/DMARC probe results.
- [conformance/onthemarket-conformance.yml](https://raw.githubusercontent.com/api-evangelist/onthemarket/refs/heads/main/conformance/onthemarket-conformance.yml): Standards conformance assessment.
- [lifecycle/onthemarket-lifecycle.yml](https://raw.githubusercontent.com/api-evangelist/onthemarket/refs/heads/main/lifecycle/onthemarket-lifecycle.yml): Versioning, deprecation, SLA and status posture.
- [packages/onthemarket-packages.yml](https://raw.githubusercontent.com/api-evangelist/onthemarket/refs/heads/main/packages/onthemarket-packages.yml): Client-library survey (no first-party packages exist).
- [llms/onthemarket-expert-llms.txt](https://raw.githubusercontent.com/api-evangelist/onthemarket/refs/heads/main/llms/onthemarket-expert-llms.txt): The one llms.txt OnTheMarket actually serves — a Yoast SEO-generated index of the OnTheMarket Expert marketing site, saved verbatim.

## Human entry points

- [Website](https://www.onthemarket.com/)
- [About](https://www.onthemarket.com/about/)
- [OnTheMarket Expert (member site)](https://expert.onthemarket.com/)
- [Help Centre](https://expert.onthemarket.com/help-centre/)
- [Contact / data-feed support](https://expert.onthemarket.com/contact-us/)
- [Join as a member agent](https://expert.onthemarket.com/join-us/)
- [Terms of Use](https://www.onthemarket.com/terms/)
- [Privacy notice](https://www.onthemarket.com/privacy/)