Ding Dong — Build Specification & Research Pack

Everything needed to build a UK residential property transaction platform. Free to use.

This is a complete, open specification for an application that runs a UK home purchase end to end — discovery, viewings, offers and negotiation, mortgage, conveyancing, completion, move-in and ongoing ownership — together with the UK market, regulatory and integration research behind it.

It was written after building and demonstrating a working prototype of the full journey. It is released freely and without conditions for the Ding Dong founders to use however they wish.

📄 Open the full specification →Plain markdown · designed to be read by an AI assistant · around 5,000 words

Give this to your AI assistant

Point Claude (or any capable coding assistant) at the link below and give it this instruction:

Read https://dingdong-spec.pages.dev/build-spec.md end to end. It is the complete specification for the application I want to build. Start with the data model and the transaction state machine, then the buyer app, then the staff back-office. Simulate every external API at the boundary the document describes, so the product is fully demonstrable before any real integration exists. Ask me anything that is ambiguous before you begin.

What's inside

The product — the ten-stage journey and the target outcomes that make it worth building
Technical architecture — the full data model, the eleven-stage transaction state machine, and the event-driven design that makes the whole thing auditable
The buyer app — every screen, including exactly how the swipe deck should feel and the mistakes that break it
The staff back-office — the human console behind every automated flow
Integrations — the real research: how UK listings actually reach portals, which estate agent systems have usable APIs, which lenders can be reached programmatically, the Land Registry APIs, searches, identity and anti-money-laundering, and where the free government property data is
Regulatory roadmap — what is legally required, in what order, and what is a criminal offence to skip
What the market teaches — why previous challengers failed, and what the survivors did differently
Build order and an honest risk register — including the constraints that cannot be engineered around

The two things that matter most

1. Listings must come from estate agents, with consent. No UK portal offers an outbound feed, and scraping carries real legal risk. No agent relationships means no inventory — this is the single biggest constraint on the business, and it is commercial, not technical.

2. The money is in the transaction, not the discovery. Every surviving end-to-end player monetises mortgage, legal and services. Discovery is customer acquisition cost. Build accordingly.

Published August 2026. Offered freely and without conditions or claim. No warranty is given — verify the regulatory position with qualified advisers before trading, as rules change. Nothing here constitutes legal or financial advice.