Sub-20ms UK Companies House API: Address Sanitization, KYB & Balance Sheet Extraction

Description and use

The API delivers sub‑20 ms access to Companies House data, normalizes addresses with GPS coordinates, classifies directors, and extracts balance sheet metrics from PDFs.

Problem

Companies House data often suffers from rate‑limit dropouts, all‑caps addresses, missing GPS coordinates, dropped leading zeroes on Scottish company numbers, and balance sheet PDFs that are hard to query or render.

Outcome

The API delivers clean, enriched data and fast PDF access, eliminating common Companies House data issues and enabling real‑time lookups in under 20 ms.

Workflow

• Send a request to the sub‑20ms API endpoint with a Companies House company number or filing ID.
• The API normalizes the address string to title case and attaches GPS coordinates.
• It categorizes directors as active or resigned.
• It scans the filing PDF, extracts balance sheet metrics, and returns them as JSON.
• If a PDF is requested, the API streams it via CORS‑enabled proxy for direct embedding.
• The response is delivered in under 20 ms.
• Use the live sandbox at https://uk-business-sanitizer-demo.jamesforsyth1829.workers.dev for testing. For Laravel, install the open‑source wrapper jamesforsyth/laravel-uk-kyb-edge from Packagist.

Evidence

Rate‑limit dropouts (HTTP 429 Too Many Requests)

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ALL‑CAPS addresses and missing GPS coordinates

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Balance sheet PDFs you can't easily query or render in browser apps

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The sub‑20ms API and web demo are live in production today!

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Address Normalization: Cleans raw strings into Title Case and attaches verified WGS‑84 GPS coordinates.

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Directors KYB: Categorizes active vs. resigned board officers instantly.

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Automated Vision Extraction: Scans filing PDFs and parses balance sheet metrics into clean JSON.

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CORS PDF Streaming: Proxies official filing PDFs directly into web portals and iFrames.

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