# FastAddress UK
> Ultra-fast, zero-dependency UK Address Autocomplete, Postcode Lookup & Ordnance Survey UPRN API and TypeScript SDK.

FastAddress UK provides deterministic sub-15ms address and postcode lookups querying over 21.1 million verified UK property records. Every address entity includes the official 12-digit Ordnance Survey Unique Property Reference Number (UPRN) and WGS84 GPS latitude/longitude coordinates.

## Core Documentation
- [Quickstart & REST API Reference](https://fastaddress.ahm-labs.com/docs): Full endpoint specification, parameters, and multi-language snippets.
- [NPM SDK Package Docs](https://fastaddress.ahm-labs.com/docs/npm): Official `@ahm-labs/fast-address-uk` package reference.
- [React & Next.js Guide](https://fastaddress.ahm-labs.com/docs/react): Drop-in React hook and checkout autocomplete component.
- [Live Latency Benchmarks](https://fastaddress.ahm-labs.com/benchmarks): Empirical P50/P95/P99 latency benchmarks vs GetAddress, Ideal Postcodes, and Loqate.
- [Free Postcode Explorer Tool](https://fastaddress.ahm-labs.com/tools/postcode-lookup): Interactive public tool to search UK postcodes and inspect raw UPRN JSON payloads.
- [Register or Report Address](https://fastaddress.ahm-labs.com/tools/report-address): Public address correction and new-build registration queue.
- [Data Provenance & Use Policy](https://fastaddress.ahm-labs.com/data-provenance): Open data licensing, statutory attributions, and appropriate use recommendations.

## Official TypeScript SDK
- **Package Name:** `@ahm-labs/fast-address-uk`
- **NPM Registry:** https://www.npmjs.com/package/@ahm-labs/fast-address-uk
- **Installation:** `npm install @ahm-labs/fast-address-uk`
- **React Hook Subpath:** `import { useFastAddress } from '@ahm-labs/fast-address-uk/react';`
- **Vanilla Subpath:** `import { lookupAddress, createFastAddressClient } from '@ahm-labs/fast-address-uk';`
- **Zero-Install CDN Script:** `https://fastaddress.ahm-labs.com/sdk/fast-address.min.js`

## REST Endpoint Specification
- **Method:** `GET`
- **URL:** `https://fastaddress.ahm-labs.com/api/v1/autocomplete?q={query}&limit={limit}`
- **Parameters:**
  - `q` (string, required): Partial or full postcode, street name, house number, or city (min 2 chars).
  - `limit` (integer, optional): Maximum suggestions returned (default: 10, max: 50).
- **Response Format:** JSON array of `{ id, address_string, postcode, latitude, longitude, uprn }`.

## Competitor Comparisons
- [FastAddress vs GetAddress.io](https://fastaddress.ahm-labs.com/alternatives/getaddress-alternative): 5.8x lower latency, free UPRN included, 60% lower cost.
- [FastAddress vs Ideal Postcodes](https://fastaddress.ahm-labs.com/alternatives/ideal-postcodes-alternative): 7.3x faster P50 latency, SQLite FTS5 engine.
- [FastAddress vs Loqate PCA Predict](https://fastaddress.ahm-labs.com/alternatives/loqate-alternative): 11x faster, lightweight JSON payloads.