GoKawiilOpen-source project runs 141,000-domain ad-blocker on $2 ESP32-C3 chip
A developer has published an open-source DNS ad-blocking project that runs on the ESP32-C3, a roughly $2 microcontroller, without requiring PSRAM. Instead of storing blocklist domains as strings in RAM, the system stores them as sorted 40-bit hashes in flash memory, allowing over 140,000 domains to fit in about 0.7MB of flash and be matched via binary search in roughly 10 milliseconds using only about 50KB of RAM.