How Truecaller Works in Microseconds

Added: 2026-06-02

[00:00:00]Ever wondered how Truecaller knows exactly who is calling you within microseconds? It's not magic. It's actually a masterclass in system design.

[00:00:08]Truecaller doesn't guess. When 40 people save a number as Rahul Pizza, that's the data. Multiply 500 million users by their contacts for a 100 billion node network. To search 100 billion records instantly, Bloom filters ignore non-existent numbers, while a Redis cache serves most lookups in just 10 milliseconds. [music] For deep searches, Cassandra handles the rest in 200 milliseconds. [music] If our AI bouncer flags behavioral patterns like sequential dialing, your screen turns red. Truecaller is a distributed voting system. Want to nail tech interviews? Go to the thinkingspeaker.com and start practicing today.