About This Service

What is this?

This service provides a fast and simple way to lookup UK telephone numbers and discover which communication provider (CP) they are allocated to. All data is sourced directly from Ofcom's official numbering allocation database.

How does it work?

When you enter a UK phone number, the system:

  1. Sanitizes and normalizes the number format
  2. Searches for progressively shorter number prefixes (e.g., 441625803040 → 44162580304 → 4416258030...)
  3. Returns the most specific matching number block
  4. Displays the allocated communication provider and status

Data Source

All numbering data comes from Ofcom's official National Numbering Scheme database, which tracks:

  • Geographic numbers (01xxx, 02xxx)
  • Mobile numbers (07xxx)
  • Corporate numbers (055xxx, 056xxx)
  • Freephone numbers (080xxx)
  • Premium rate numbers (09xxx)
  • And many other number ranges

The database is automatically updated daily to ensure you always have the latest information.

API Access

This service provides a simple REST API for programmatic access. No authentication required!

Single lookup:
GET /api/lookup?number=441625803040

Bulk lookup:
GET /api/lookup?numbers=441625803040,442012345678

View Full API Documentation

Rate Limiting

To ensure fair usage and service availability, we implement rate limiting:

  • 10,000 lookups per hour per IP address
  • Rate limits apply to both web UI and API
  • Check your current usage at /api/rate-limit

Privacy

This service is designed with privacy in mind:

  • No user accounts or registration required
  • No server-side storage of your lookups
  • Recent lookups stored locally in your browser only
  • Only rate limiting data (IP counters) stored temporarily

Use Cases

This service is useful for:

  • Identifying the provider for unknown caller IDs
  • Validating phone number databases
  • Telecommunications research and analysis
  • Number portability tracking
  • Compliance and regulatory purposes

Limitations

Please note:

  • This service shows the original allocating provider, not necessarily the current provider if the number has been ported
  • Individual subscriber information is not available (only number block allocations)
  • Data is updated daily, so very recent changes may not be reflected immediately

Open Source

This service is built with modern web technologies and best practices to ensure fast, reliable performance. The focus is on speed, security, and user privacy.