This is not our API. This repository is an independent, third-party profile of a company's publicly available API surface, maintained by API Evangelist. API Evangelist does not operate, host, resell, or support this company's APIs, and is not affiliated with or endorsed by the company unless stated on the profile.
Where the information came from. Everything here is assembled from material a member of the public can reach with a browser and no credentials — the company's own website, developer portal and documentation, the specifications it publishes for public use (OpenAPI, AsyncAPI, JSON Schema,
apis.json,llms.txtand similar), its public repositories, and its public status, pricing and changelog pages. Nothing here is obtained by breaching a system, defeating an access control, or using credentials of any kind.The rating is an independent assessment. The Kin Score and Agent Readiness rating are independently calculated scores of a company's public API artifacts, produced by API Evangelist against a published rubric. They are not certifications, endorsements, security assessments, or audits, and they score published artifacts — not the quality, safety, or security of the software.
Corrections, re-scores, and removal are free. No partnership, contract, or purchase is required, and you do not need to justify the request.
- Something wrong? Open an issue on this repository, or email info@apievangelist.com.
- Published something new? Ask for a re-score and we will re-run the rating.
- Want the listing taken down? Say so and we will honor it. The profile is reduced to your company name, a factual description, and a link to your own site, and the company is recorded as unrated — never scored zero for having asked.
Response times. Acknowledgement within one business day; removal or restriction within two business days; corrections and re-scores within five business days.
Not from the company, and here with a question? You are welcome here — we would rather be the front line and point you the right way than have a good report go nowhere. What this repository can answer is narrow, though, so it is worth knowing who you are actually looking for:
- A question about how the API works, an account, billing, or a bug in the service — that is the company's own support, not us. We profile this API; we do not operate it and cannot see your account.
- A bug in an open-source project we only catalog — file it on that project's own repository. This has happened with a real and correct bug report that reached us instead of the people who could fix it, which helped nobody.
- Anything about this listing itself — the description, the tags, the rating, a missing or wrong artifact — is ours. Open an issue here.
- Not sure, or something general about API Evangelist or APIs.io — open an issue on the APIs.io Inbox and we will route it.
This repository contains no software, and we will never ask you to download anything. There is no build, release, installer, or binary here — only text and machine-readable API descriptions, so there is nothing here that can be "corrupt" or need "repairing". Any issue, comment, or email claiming otherwise and offering a download link is not from us and is hostile. Do not follow the link; it is a lure. Report it to GitHub and, if you like, tell us at info@apievangelist.com so we can take it down.
On a security or compliance team? Email info@apievangelist.com with security in the subject line and you will get a person, not a form. We will tell you exactly which public URLs this profile was built from so your team can see the same surface we did, and we will take the listing down on request while you work through it.
Full detail: Where this data comes from
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.
APIs.json: https://raw.githubusercontent.com/api-evangelist/onthemarket/refs/heads/main/apis.yml
- 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
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.
- Human URL: https://expert.onthemarket.com/contact-us/
- Base URL:
https://realtime-api.onthemarket.com/v1
- Data Feed
- Property Listings
- Leads
- Estate Agents
- Website
- About
- Terms of Service
- Blog
- Partners
- Support
- Sign Up
- Login
- GitHub Organization
- Parent Company
Certified: No. Posture: No RESO reference found anywhere on OnTheMarket's properties.
RESO is a North American (NAR/MLS) construct and the United Kingdom has no MLS to certify against. https://www.reso.org/certificates/ was fetched anonymously (HTTP 200) and contains no reference to OnTheMarket or to any United Kingdom organization; https://certification.reso.org/ returned HTTP 400 to an anonymous client. No OData service document or $metadata exists — probes of https://www.onthemarket.com/$metadata and https://realtime-api.onthemarket.com/$metadata both returned HTTP 404. There is no Universal Property Identifier; OnTheMarket uses its own opaque property identifiers. The only interoperable convention in this market is a de facto one — the Rightmove BLM/RTDF format that OnTheMarket and Openbrix also accept — with no governing body, no certification and no version registry behind it.
Gate: membership-required — you must be an OnTheMarket member estate agent, homebuilder or developer with a listing agreement, or the CRM software vendor integrating on that member's behalf. There is no developer programme, no API terms page, no application form and no key self-issuance on any OnTheMarket property. Membership is arranged commercially via expert.onthemarket.com/join-us; data feeds are set up by OnTheMarket support (support@onthemarket.com, 0808 1202 877). The Terms of Use are themselves part of the gate — clause 3.3 prohibits automated access to any page other than the home page.
None. OnTheMarket publishes no open, unlicensed, publicly callable dataset. Sold prices and the free instant-valuation AVM (built with Property Price Advice) are consumer web pages, not data products. The genuinely open UK property layer belongs to the public sector — HM Land Registry Price Paid Data under the Open Government Licence and Ordnance Survey's open addressing and mapping products — and none of it comes from the portals.
Not published. Consistent with its Rightmove RTDF lineage, the connection is mutual TLS with a client certificate rather than a bearer token; integrators are told to support TLS 1.1/1.2 and SHA-1 PEM certificates. No API keys, no OAuth 2.0, no SAML and no OIDC discovery document are served on any OnTheMarket host (/.well-known/openid-configuration returned HTTP 404).
- Kin Lane — kin@apievangelist.com