Supported Ranges:
India: +916xxxxxxxxx – +919xxxxxxxxx (4 billion numbers)
Singapore: +658xxxxxxx – +659xxxxxxx (20 million numbers)
How this works?
The phonebook is achieving sub-millisecond performance by using binary search with O(log n) complexity for instant hash lookups. Phone numbers are not stored; instead, they are reconstructed from indices on the fly during lookup operations. The rainbow table for India and Singapore range spans approximately 161 GB, containing 4.02 billion entries at 40 bytes each (32 bytes for the SHA256 hash plus 8 bytes for the index). Data is stored efficiently in memory-mapped binary files, no external database is used. Built with Rust using memmap2 for memory mapping, Rayon for parallel processing, and Actix Web for serving this interface.