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Captcha & Detection

Bot detection, Google Search, trust tiers, and real-world gatekeeping.

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Dev story — work in progress

These posts are engineering notes from building Koko. They capture what we believed at the time — some lessons aged well, some did not. Treat them as a lab notebook, not official docs. Corrections and better ideas are welcome.

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All Bug Stories1 Captcha & Detection1 Performance1 SDK1 Browser Engine1

Captcha & Detectioncaptcha/detection/google-search-investigation-journey.md

Google Search Investigation Journey — What We Thought, Tested, and Finally Understood

For months, Koko Google Search behaved like a fingerprint problem: CreepJS sections were green, wire headers were tuned, encode was patched — yet the same query on the same IP still returned a 91 KB bootstrap shell instead of Chrome’s 270–600 KB SERP on hop 1. The breakthrough was not another JS s

June 30, 2026

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