Listings
Homes to let and for sale, with the fields Dutch law makes a listing carry: the rent segment and its points score, the legal rent ceiling, the energy label, and what is sold.
RESO Web API · Local_NL_
Open listing catalogue · for portals, platforms and developers
RESOnance is a catalogue that holds no key
RESOnance publishes rental and sale listings for Dutch residential housing on the RESO Web API, the data standard the industry already speaks. It matches a renter's or a buyer's sealed verdict against what a listing requires and learns nothing else, and it holds no signing key, so it cannot forge the matches it makes.
- PublisherThe agency's lifecyclelists the home and signs each public act
- publishes to
- CatalogueRESOnanceserves listings and the log, and verifies what is presented
- is read by
- ConsumerA portal, a platform or anyonereads the standard API and checks the log without an account
For portals, platforms and developers
A Dutch profile of an open standard
A portal or platform reads RESOnance as it reads any RESO source. What is Dutch about it is written down, not left for a reader to reverse-engineer.
- RESO Web APIListings are served on the standard's property resource, validated as metadata on Data Dictionary 1.7 by RESO's own tool, run against the live catalogue.
- Rental and sale on one resourceA sale is the standard's Residential property, a rental its Residential Lease, and the Dutch market stage travels beside the standard's status.
- Extensions with their sourceEach Dutch field is listed with its type, its vocabulary and the statutory instrument it carries, and the permitted values are served as a Lookup resource.
- Viewings any portal can showViewing times are published on the standard's open-house resource, with their timezone.
Specifications RESOnance uses
- RESO Web APIOData, the industry's listing API
- Data Dictionary 1.7RESO's field definitions
- RFC 9162a Merkle log that can only grow
- SD-JWT VCverifying what holders present
What RESOnance publishes
Listings, a log and figures nobody can inflate
A signed public log
Every public act in a rental or a sale is a leaf in a signed log that can only grow, so anyone can check the order in which a procedure ran.
RFC 9162 · ES256A register of figures
How long a rental took, how many applied, whether it completed, and what homes sold for: per listing, per office and per city, each drawn from the log rather than from a report.
derived from the log
A viewing only for someone who qualifies
The verdict comes before the viewing. Renters who hold one book a slot themselves, first come, with no score; a renter below a listing's published requirement takes a slot only if the agent admits them, and that decision is logged.
The log
A history nobody can quietly rewrite
The log is built as an RFC 9162 Merkle tree, the construction that made the web's certificate authorities auditable. The whole history hashes up to one value, and that value is what gets signed.
- The signed headOne commitment to the whole log, signed with ES256 by the orchestrator, not by the catalogue that serves it.
- An inclusion proofThe path from any single entry to that head, in log n steps rather than n.
- A consistency proofWhether an older head is still contained in today's. This is the check that catches a rewritten history.
- No account, no permissionEach of the three is a plain request anyone can make, and the catalogue recomputes the tree holding no key.
For public institutions
A market that can prove itself
For those who enforce the law
An agency no longer only asserts that it ran a lawful procedure: the listing, the mandate, the applications and bids, the credentials and the award are entries in the log, and their order can be checked by a regulator or a municipality without asking anyone for access.
A figure in the register is checked against the record, not trusted from whoever reports it.
regulators · supervisors · courts · municipalitiesFor those who make the law
Most of the catalogue's Dutch fields derive from statute: the rent segments of the Affordable Rent Act, the points score that determines them, the room-rental permit regime, and the contract designations of the Civil Code. A field that encodes a statute changes when the statute changes.
The profile is a working one, written by one implementer. No Dutch body has adopted it and RESO has not reviewed it.
parliament · ministries · advisory councils
What the catalogue learns
The issuer's yes or no, not the income behind it
A match is made on predicates rather than on a file. What RESOnance learns is the issuer's sealed answer for this home at this rent.
Presented
affords_target_rent: trueWhat a renter presents to RESOnance for one listing.
Privacy
No person is a leaf
The public record carries facts about transactions, never about the people in them.
- No handle for a personNo per-person handle exists on the public record at all.
- Small numbers in rangesFigures derived from people, such as how many applied, and any agency with fewer than ten lettings, are shown in ranges until at least ten stand behind them.
- Keyless, and provably soThe catalogue issues nothing and signs nothing. A wire contract and a source-wide check fail the build if that ever changes.
- Issuers on an allowlistTrust is resolved through a configured list of issuers, so a credential from another issuer verifies on the same path as one from Tacit.
Contact
Write to RESOnance
For integration, partnership and technical questions. Your message is delivered by email and is not stored on this website.