OnTheMarket

aid: onthemarket
url: https://raw.githubusercontent.com/api-evangelist/onthemarket/refs/heads/main/apis.yml
name: OnTheMarket
kind: company
description: 'OnTheMarket is the third-largest residential property portal in the United Kingdom, operating onthemarket.com.
  It was founded in 2013 by Agents'' Mutual Limited as an agent-owned challenger to Rightmove and Zoopla, listed on AIM as
  OnTheMarket plc, and was acquired outright by CoStar Group in December 2023 for approximately GBP 99 million. In a market
  with no MLS and no cooperative listing standard, OnTheMarket sits at the demand end of the value chain: consumers search
  the portal, and listings arrive from member estate agents'' CRM systems rather than from a shared data pool. Its API posture
  is honest and narrow. There is no public developer portal — developer., developers., api. and docs.onthemarket.com do not
  resolve, and /developers, /api, /docs, /openapi.json, /swagger.json and /api-docs all return 404 on the main site. What
  does exist is a member-only integration surface: the OnTheMarket Real Time Datafeed (RTDF), a Rightmove-RTDF-compatible
  feed API served from the live, OnTheMarket-operated host realtime-api.onthemarket.com, used by agency CRM vendors to push
  listings and pull branch enquiries on behalf of member agents. No machine-readable contract for it is published anywhere;
  OnTheMarket''s developer guide is distributed under agreement, and every path on the host returns 404 to an anonymous caller.
  There is no RESO Web API or Data Dictionary certification, no OData $metadata document and no Universal Property Identifier
  anywhere in the stack — RESO is a North American construct and the UK has never adopted it, so "certified but unreachable"
  does not apply here; there is no certification layer in this market at all. OnTheMarket publishes no open data. The genuinely
  open UK property layer belongs to the public sector — HM Land Registry Price Paid Data and Ordnance Survey — and none of
  it comes from the portals. OnTheMarket''s own Terms of Use go further than most and expressly forbid automated access to
  any page other than the home page.'
accessModel:
  pricing: paid
  onboarding: membership-required
  trial: false
  try_now: false
  public: false
  label: Paid · OnTheMarket agent membership and a data-feed agreement required
  confidence: high
  source:
  - terms-of-use
  - documentation
  - probes
  generated: '2026-07-26'
  method: manual
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/onthemarket.png
tags:
- Real Estate
- United Kingdom
- Property Listings
- Property Portal
- PropTech
- Rentals
- Estate Agents
- Data Feed
- New Homes
- Commercial Real Estate
created: '2026-07-26'
modified: '2026-07-26'
specificationVersion: '0.19'
apis:
- aid: onthemarket:onthemarket-real-time-datafeed-api
  name: OnTheMarket Real Time Datafeed (RTDF) API
  description: '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.'
  humanURL: https://expert.onthemarket.com/contact-us/
  baseURL: https://realtime-api.onthemarket.com/v1
  tags:
  - Data Feed
  - Property Listings
  - Leads
  - Estate Agents
  properties:
  - type: Website
    url: https://expert.onthemarket.com/
  - type: Support
    url: https://expert.onthemarket.com/contact-us/
common:
- type: DomainSecurity
  url: security/onthemarket-domain-security.yml
- type: Conformance
  name: Standards conformance assessment (derived)
  url: conformance/onthemarket-conformance.yml
- type: Lifecycle
  name: Versioning, deprecation, SLA and status posture
  url: lifecycle/onthemarket-lifecycle.yml
- type: Packages
  name: Client-library survey (no first-party packages)
  url: packages/onthemarket-packages.yml
- type: LLMsTxt
  name: API Evangelist-generated llms.txt for OnTheMarket
  url: llms/onthemarket-llms.txt
- type: LLMsTxt
  name: OnTheMarket Expert llms.txt (published by OnTheMarket, saved verbatim)
  url: https://expert.onthemarket.com/llms.txt
- type: Website
  url: https://www.onthemarket.com/
- type: About
  url: https://www.onthemarket.com/about/
- type: TermsOfService
  url: https://www.onthemarket.com/terms/
- type: PrivacyPolicy
  name: Privacy notice (redirects to the CoStar Group global privacy notice)
  url: https://www.onthemarket.com/privacy/
- type: Blog
  url: https://www.onthemarket.com/content/
- type: BlogRSS
  url: https://www.onthemarket.com/content/feed/
- type: HelpCenter
  name: OnTheMarket Expert Help Centre (member-facing)
  url: https://expert.onthemarket.com/help-centre/
- type: Partners
  url: https://expert.onthemarket.com/our-partners/
- type: Support
  url: https://expert.onthemarket.com/contact-us/
- type: SignUp
  url: https://expert.onthemarket.com/join-us/
- type: Login
  url: https://expert.onthemarket.com/apps/login
- type: GitHubOrganization
  url: https://github.com/OnTheMarket
- type: LinkedIn
  url: https://www.linkedin.com/company/onthemarket/
- type: ParentCompany
  url: https://www.costargroup.com/
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com