{"slug": "i-built-a-privacy-focused-search-engine-from-scratch-and-learned-why-search-is", "title": "I built a privacy-focused search engine from scratch (and learned why search is hard)", "summary": "A developer built Slick, an independent, privacy-focused search engine from scratch, learning that search is far more complex than it appears. The engine combines traditional keyword matching with semantic search using embeddings, and relies on Elasticsearch for indexing while currently using DuckDuckGo's index as it matures.", "body_md": "I built [Slick](https://slicksearchhq.com) because I wanted a search engine that actually felt like it belonged to the user.\n\nNot another search wrapper.\n\nNot another app that just sends your query somewhere else.\n\nA real search engine.\n\nAt first, I thought:\n\n\"How hard could it be?\"\n\nYou crawl some websites, put them in an index, add a search box, and you're done... right?\n\nTurns out, not even close.\n\nSearch is one of those things that looks simple until you try to build it yourself.\n\nSlick is an independent, privacy-focused search engine that I'm building from scratch.\n\nThe goal is simple:\n\nGive users more control over how they search the web.\n\nFeatures include:\n\nThe project started as an experiment, but quickly became a deep dive into crawling, information retrieval, machine learning, and infrastructure.\n\nA search engine is useless without an index.\n\nThe first major component I built was the crawler.\n\nIt needs to:\n\nThe goal isn't to blindly crawl the entire internet.\n\nThe goal is building a useful, high-quality index.\n\nFor indexing, Slick uses Elasticsearch. By default we use DuckDuckGo's index, as Slick is still maturing.\n\nEach document contains information like:\n\nThe initial search system uses traditional information retrieval techniques like BM25.\n\nBut keyword matching has a problem.\n\nA user doesn't always search using the exact words found on a page.\n\nFor example:\n\n\"how do I stop websites tracking me\"\n\nand:\n\n\"privacy tools that prevent online surveillance\"\n\nmean almost the same thing.\n\nA keyword-only search engine sees two different queries.\n\nHumans don't.\n\nTo improve this, Slick uses semantic search.\n\nPages and queries can be converted into embeddings that represent meaning instead of just text.\n\nThe ranking pipeline combines:\n\nThe idea is to combine the strengths of old-school search with modern machine learning.\n\nGetting results is easy.\n\nGetting the right results is hard.\n\nA search engine can return thousands of pages that technically match a query.\n\nBut users don't want thousands of pages.\n\nThey want the one that answers their question.\n\nRanking involves constantly asking:\n\nThis is where most of the engineering effort goes.\n\nThe biggest surprise was how much infrastructure search requires.\n\nThe UI is honestly the easy part.\n\nThe difficult parts are:\n\nLarge search engines have entire teams dedicated to one small part of this.\n\nBuilding even a small one makes you appreciate how much work happens behind every search box.\n\nSlick is still actively being developed.\n\nSome areas I'm working on:\n\nThe long-term goal is not to make \"another Google clone.\"\n\nIt's to explore what search looks like when users have more control.\n\nIf you want to try it:\n\n[https://slicksearchhq.com/](https://slicksearchhq.com/)\n\nThe project is still early, so any feedback, suggestions, or ideas are greatly appreciated.\n\nThanks for checking it out!", "url": "https://wpnews.pro/news/i-built-a-privacy-focused-search-engine-from-scratch-and-learned-why-search-is", "canonical_source": "https://dev.to/noxxe21125/i-built-a-privacy-focused-search-engine-from-scratch-and-learned-why-search-is-hard-l0", "published_at": "2026-07-24 19:18:20+00:00", "updated_at": "2026-07-24 19:32:54.239372+00:00", "lang": "en", "topics": ["developer-tools"], "entities": ["Slick", "Elasticsearch", "DuckDuckGo"], "alternates": {"html": "https://wpnews.pro/news/i-built-a-privacy-focused-search-engine-from-scratch-and-learned-why-search-is", "markdown": "https://wpnews.pro/news/i-built-a-privacy-focused-search-engine-from-scratch-and-learned-why-search-is.md", "text": "https://wpnews.pro/news/i-built-a-privacy-focused-search-engine-from-scratch-and-learned-why-search-is.txt", "jsonld": "https://wpnews.pro/news/i-built-a-privacy-focused-search-engine-from-scratch-and-learned-why-search-is.jsonld"}}