OS Linked Identifiers API
The OS Linked Identifiers API allows you to access the valuable relationships between properties, streets and OS MasterMap identifiers (TOIDs). Benefit from the valuable relationship found in OS Premium products. Link together datasets that are using different identifiers; for example, linking a property address (UPRN) to the street that it’s on (USRN). The OS Linked Identifiers API allows users to access the valuable relationships between properties, streets and OS MasterMap identifiers for free. An identifier is a unique reference assigned to a specific thing, so when you are talking to someone else you can use it to ensure you.
Trust score
How is this computed?Composite of 5 axes from our methodology (proof-based officialness, live verification, metadata completeness, license clarity, agent readiness).
- Officialnessweight 25%50/100
Not public-sector → neutral score; not subject to the proof checker.
- Availabilityweight 25%100/100
Latest verification succeeded.
- Metadata completenessweight 20%30/100
3 of 10 recommended metadata fields populated.
- License clarityweight 15%50/100
License info not yet tracked for APIs (datasets only).
- Agent readinessweight 15%10/100
Topic tags assigned
Data access
This entry links to a dataset, file download, or documentation page rather than a self-describing API, so there's no field schema to display.
Verification Status
Using the API
Configuration
- Base URL
- https://api.os.uk
Query examples
curl -s 'https://api.os.uk' -H 'Accept: application/json'Base API endpoint — see the documentation for available routes.