--- title: An NSFW filter for Marginalia Search | daily.dev description: A developer building Marginalia Search documents their journey implementing an NSFW content filter from scratch. After finding transformer-based models too... canonical: https://daily.dev/posts/an-nsfw-filter-for-marginalia-search-gqzn4pskl twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: An NSFW filter for Marginalia Search | daily.dev og:description: A developer building Marginalia Search documents their journey implementing an NSFW content filter from scratch. After finding transformer-based models too... og:url: https://daily.dev/posts/an-nsfw-filter-for-marginalia-search-gqzn4pskl og:image: https://api.daily.dev/og/posts/GQzN4PSKL.png og:image:alt: An NSFW filter for Marginalia Search og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # An NSFW filter for Marginalia Search **[Hacker News](https://daily.dev/sources/hn)** · 14 min read · 2 upvotes · 0 comments ## Summary A developer building Marginalia Search documents their journey implementing an NSFW content filter from scratch. After finding transformer-based models too slow for real-time search use, they tried fasttext but got poor results due to biased training data. They solved the labeling problem by using ollama+qwen3.5 as an LLM-based annotator to generate training samples at scale. The final solution is a single hidden layer neural network with hand-picked features and chi-squared scoring for disambiguation, implemented in Java. The post includes full math derivations for forward propagation, backpropagation, and gradient descent, plus evaluation metrics showing ~90% accuracy on training data with caveats about real-world false positive rates due to low NSFW base rates. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [How we think about text classification in the LLM era](https://daily.dev/posts/how-we-think-about-text-classification-in-the-llm-era-ccij6y48x) · Medium Engineering · 1 upvotes · 0 comments - [Job Searcher](https://daily.dev/posts/job-searcher-jnnq5luqj) · Hugging Face · 19 upvotes · 1 comments - [Unsloth's new desktop app does the one thing LM Studio and Ollama never let me do](https://daily.dev/posts/unsloth-s-new-desktop-app-does-the-one-thing-lm-studio-and-ollama-never-let-me-do-k73yb5rml) · XDA Developers · 1 upvotes · 0 comments - [How Vision Language Models Are Trained from “Scratch”](https://daily.dev/posts/how-vision-language-models-are-trained-from-scratch--cptxwc95l) · Towards Data Science · 0 upvotes · 0 comments --- Tags: [#machine-learning](https://daily.dev/tags/machine-learning), [#deep-learning](https://daily.dev/tags/deep-learning) [View this post on daily.dev](https://daily.dev/posts/an-nsfw-filter-for-marginalia-search-gqzn4pskl) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"An NSFW filter for Marginalia Search","url":"https://daily.dev/posts/an-nsfw-filter-for-marginalia-search-gqzn4pskl","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/an-nsfw-filter-for-marginalia-search-gqzn4pskl"},"datePublished":"2026-03-30T23:19:23.916Z","dateModified":"2026-03-30T23:19:54.565Z","description":"A developer building Marginalia Search documents their journey implementing an NSFW content filter from scratch. 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