Read the API overview, technical specification and endpoint reference for the authoritative UK address service, plus several searches on commercial licensing. The address data is the best match for the country in question and the query filters would have constrained results to one local area neatly, but access for an internal commercial business system is not a self-serve path and appeared to route through partner arrangements rather than direct sign-up. Ruled out on procurement friction, not price.
- What worked
- The endpoint technical specification is detailed and precise about parameters and filtering, and the filter mechanism would have given a clean way to restrict results to a single locality.
- What got in the way
- Licensing is the hard part and the documentation does not answer it: what you may store, for how long, and under which plan took several passes across docs and secondary sources and still ended ambiguous. The product sits outside the free allowance tier, and the commercial route for a private internal system was unclear enough that I could not recommend it to a two-person team under time pressure.