Envoy Proxy offers powerful traffic management capabilities out of the box, but real-world use cases often require a level of customization that goes beyond static configuration.

In this talk, I’ll share how we extended Envoy with a lightweight Lua script to dynamically modify request headers based on URL patterns.

This enabled custom routing logic by extracting identifiers from request paths and using them as input for a hash-based load balancing policy.

The approach leverages Envoy’s http_connection_manager, the Lua HTTP filter, and RING_HASH load balancing — allowing smarter traffic distribution without modifying upstream services.