Dev Tools · 11h ago
Hacker packs 537K blocked domains into $5 ESP32 ad-blocking dongle
A developer created a DNS-based ad blocker using a $5 ESP32 microcontroller that stores 537,000 domains in 4MB of flash via a hashing trick. The firmware uses only 50KB of RAM and responds to blocked lookups in 10 milliseconds. The project demonstrates efficient data compression for low-cost hardware.
Meridian48 take
While clever, the dongle's reliance on a static blocklist means it won't catch new threats without firmware updates, limiting its practical use against dynamic ad networks.
Read the full reporting
Clever hacker fits 537,000 domains in a tiny $5 ESP32 ad-blocking dongle — firmware uses only around 50KB of RAM and can answer blocked lookups in 10 milliseconds →
Tom's Hardware
esp32ad-blocking