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ESP32-C3 ad blocker searches a 140,000-domain list from flash

github.com 8 min read Editor score 7/10

The project stores sorted 40-bit domain hashes in flash and binary-searches them, fitting over 140,000 entries in about 0.7 MB while using about 50 KB of RAM. The memory-versus-latency trade-off is a useful example of engineering under tight resource constraints.

What: ESP32-C3 Adblock is a Pi-hole-style DNS ad blocker that runs without PSRAM.
How: It stores sorted 40-bit domain hashes in flash and binary-searches them; over 140,000 domains fit in about 0.7 MB.
Why it matters: Flash-resident hashes reduce RAM demands, a storage tradeoff the excerpt says also works on larger chips.

DNS queries are hashed and checked in flash, then sinkholed on a hit or forwarded on a miss. Sketched from the article's own text.

Read on github.com → Hacker News · 21 comments

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