Semantic Scholar

Semantic Scholar is the leading free AI-powered academic search engine, indexing 234 million+ scientific papers across all fields of science. Built and maintained by the Allen Institute for AI (Ai2) since 2015 — the nonprofit AI research lab founded by Paul Allen — the platform is funded by research grants and Ai2's mission rather than commercial subscriptions, making it permanently free for researchers, students, and developers. Pricing is fully free with no paid tier. The web interface provides search, paper details, citation networks, author profiles, and AI-powered features (TLDR summaries, recommended papers, influence-based ranking). The Semantic Scholar Open Research Corpus API is freely available with reasonable rate limits, providing programmatic access to paper metadata, abstracts, citations, references, and full-text content where available — used by hundreds of academic tools and AI research applications including Elicit, Consensus, ResearchRabbit, and Connected Papers. Semantic Scholar's differentiation versus Google Scholar is the structured data and AI-augmented features: TLDR provides one-sentence AI summaries of papers, citation context distinguishes supportive citations from contradicting ones, and influence ranking weighs citations by their impact rather than raw count. The Semantic Reader (in beta) augments PDF reading with inline citation context, definition lookup, and related work surfacing — features that traditional academic search engines cannot match. The platform supports all major academic disciplines (computer science, biomedical, physics, chemistry, social sciences, humanities) with depth varying by field. Indexing pulls from publisher feeds, preprint servers (arXiv, bioRxiv, medRxiv), institutional repositories, and OpenAlex. Coverage is most comprehensive for English-language literature in indexed databases; less complete for non-English humanities journals and small-press publications. Ai2 operates under research-grade infrastructure with academic data ethics standards.