Free AI Tools

Weaviate is an open-source vector database with HNSW indexing. GraphQL API for queries. Multi-model: combine vectors and structured data. Semantic search and RAG out of box. Cloud-hosted option. Growing adoption.

A document AI platform enabling natural language conversation with uploaded PDFs, Word documents, text files, and PowerPoint files, as well as documents loaded from URLs or Google Drive links. AskYourPDF stores documents in a personal knowledge library and lets users query across multiple documents simultaneously, asking a question and getting a synthesized answer from several sources. A team workspace lets shared documents be queried by all members. An API allows developers to embed document Q&A into their own applications. The platform also supports web-based research where users submit a URL and ask questions about the page content. Free plan covers basic document chat with limited messages; Pro is $9.99/month. Popular with legal professionals, consultants, researchers, and business analysts who work with large volumes of document-based information.

A web tool that lets users upload any PDF document and have a natural language conversation with its contents using AI. Users ask questions about the document and ChatPDF retrieves and synthesizes relevant passages to generate a direct answer with page references. It works for research papers, legal contracts, financial reports, textbooks, manuals, and any other document-based content. The tool handles documents up to several hundred pages and retains context across multiple questions in the same session, making it possible to explore a complex document through conversation rather than linear reading. A summary is auto-generated when a document is first uploaded. Free plan covers 2 PDFs per day up to 120 pages each; Pro is $5/month for more PDFs, larger files, and higher message limits. Popular with students reading academic papers, lawyers reviewing contracts, and analysts processing reports.

A visual research tool that generates a graph showing relationships between academic papers based on citation networks and semantic similarity. Researchers enter a seed paper they consider relevant to their topic, and Connected Papers builds a visual map of related work, clustering similar papers together and showing how closely each paper is connected to the seed through edge thickness and node proximity. This helps researchers quickly identify the most influential papers in a field, find seminal works they might have missed, and see which papers are highly cited together. Papers can be clicked to open in their source database. The graph view is more intuitive for exploring a field than a list of search results, making it especially useful at the start of a literature review. Free plan allows 5 graph builds per month; Pro is $3/month for unlimited graphs. Popular with academics, graduate students, and research analysts.

Duolingo has integrated AI throughout its language learning app, with the most significant additions in Duolingo Max, the premium AI tier. Explain My Answer is an AI tutor that explains why a user's response was correct or incorrect in natural language rather than showing a generic error message. Roleplay lets users practice real-world conversational scenarios with an AI character in the target language, covering situations like ordering food, asking for directions, or making plans. The existing spaced repetition algorithm uses AI to schedule vocabulary review at the optimal time for each individual learner. Duolingo's AI also powers audio comprehension practice, adaptive hint systems, and sentence-level translation exercises. Free tier covers core lessons; Duolingo Max with full AI features is $29.99/month. Duolingo has over 500 million registered users globally, making it the world's most used language learning platform.

An AI English pronunciation and speaking coach app that uses speech recognition to detect and correct pronunciation errors at the level of individual phonemes. Unlike apps that only transcribe speech, Elsa analyzes precisely which sounds are mispronounced, why they are incorrect, and provides targeted exercises to correct the specific mouth position and airflow needed for each sound. The app builds a personal pronunciation profile for each learner based on their native language and detected weaknesses, then creates a customized learning path. Elsa covers over 22,000 English words and includes practice with sentences, conversations, and business scenarios. Users practice being understood in meetings, on video calls, at the doctor, and in other real-life situations. Free plan includes limited daily lessons; Elsa Pro is $11.99/month or $59.99/year. Used by over 7 million people in 101 countries learning to speak English more clearly.

AI tool that explains complex sections of research papers simply.

The AI tutor from Khan Academy, built on GPT-4 and designed around Socratic teaching methods rather than just giving answers. Instead of solving problems directly for students, Khanmigo asks guiding questions that help them reason through solutions themselves, supporting deeper learning rather than answer copying. Khanmigo works across Khan Academy's full curriculum including math, science, history, computing, and economics, and also tutors for SAT and AP exam preparation. A teacher mode lets educators use Khanmigo to generate lesson plans, quiz questions, writing rubrics, and ideas for explaining difficult concepts in new ways. A writing coach guides students through essay structure without doing the writing for them. Available to Khan Academy learners for $4/month as an individual add-on, with free access available through school and district partnerships. Used by millions of K-12 students and families globally.

A literature mapping and paper discovery tool that helps researchers visualize and navigate scientific literature networks. Litmaps generates a timeline graph showing how papers in a field relate to each other and how research has evolved over time. A Seed Map feature starts from one or more known relevant papers and grows outward to discover connected works through citation relationships. The Discover feature continuously monitors for new papers matching the researcher's topic profile and sends email alerts when relevant new research is published. Notes and highlighting tools allow researchers to annotate papers within the platform. Litmaps integrates with Zotero, Mendeley, and Excel for managing reference lists. Free plan allows 2 active maps; paid plans start at $10/month. Popular with PhD students, research scientists, and systematic review teams building comprehensive literature maps.

AI math solver that explains step-by-step solutions from camera input.

Quizlet is a study platform with over 600 million study sets and has integrated AI to make learning more adaptive. Q-Chat is an AI tutor that teaches material through conversation, asking questions and adapting based on where the student is struggling, rather than letting students passively flip through flashcards. AI-generated explanations provide step-by-step breakdowns of wrong answers. The Magic Notes feature converts pasted lecture notes, textbook passages, or PDFs into a complete set of flashcards, a practice quiz, and a matching game automatically. Smart Grading evaluates written answers to open-ended questions rather than requiring exact text matching. Quizlet is free for basic use; Quizlet Plus is $7.99/month for ad-free access and all AI features. Used by over 60 million students globally, particularly in high school and university courses.

A free AI-powered academic research discovery tool that visualizes connections between scientific papers and helps researchers find related work they might have missed. Users add papers to a collection, and Research Rabbit maps the citation network visually, showing which papers cite the ones already read and which other papers those authors have published. A recommendation engine surfaces similar papers from outside the citation network based on semantic similarity. Saved collections sync with Zotero for reference management. Collaboration features allow research teams to share and annotate collections together. Email digests alert users when new papers matching their research interests are published. Research Rabbit is completely free, funded by a non-profit model. Popular with academic researchers, PhD students, and evidence-based professionals mapping the literature in an unfamiliar field.

An AI research assistant for reading, understanding, and exploring scientific papers. SciSpace's core feature is the AI Copilot for PDFs: users upload or open any research paper and ask the AI questions about specific paragraphs, request simplifications of technical jargon, ask for explanations of equations, and get summaries of individual sections. A literature search feature finds papers related to a query and generates a structured summary of findings across multiple studies. SciSpace also produces literature review drafts by synthesizing findings from a set of selected papers. The platform hosts over 200 million research papers. A Paraphraser and Citation Generator assist with academic writing. Free plan covers basic features; Pro is $20/month for unlimited AI interactions. Popular with graduate students, academic researchers, and professionals who need to process large volumes of scientific literature quickly.

AI-powered academic search engine for finding and analyzing research papers.

A free mobile app from Google that helps students get explanations and hints for homework questions without just giving them the answer directly. Students take a photo of a problem or type a question, and the app identifies the subject and provides step-by-step guides, video explanations, and concept summaries to help them understand the material. Socratic draws on content from Khan Academy, Crash Course, and other educational resources, as well as Google's own AI, to surface the most relevant explanation for each specific question. It covers math including geometry and calculus, science including biology, chemistry, and physics, history, and literature analysis. The AI explains the concepts needed to approach the problem rather than solving it for the student. Free to use with no subscription. Available on iOS and Android. Popular with middle and high school students doing independent study.

A free web tool that generates AI summaries of YouTube videos from a URL, making it possible to get the key points of any long video without watching it. Users paste a YouTube link and the tool transcribes the video and uses AI to condense it into a structured summary with main topics, key arguments, and important details. The summary includes timestamps linking back to relevant sections of the original video. Works for educational lectures, conference talks, podcasts published as video, documentary content, how-to tutorials, and product demos. For very long videos over 30 minutes, the summary captures overall structure and highlights rather than every detail. The tool is free to use with no account required for standard summaries. Popular with students reviewing long lecture recordings, professionals evaluating conference talks before committing to watching, and researchers assessing whether a video contains relevant information.

A generative image platform based on collaborative evolution and blending of images. Artbreeder's core feature is Splicer, which blends two or more images together with sliders controlling how much of each parent image contributes to the result, creating a continuous spectrum of variations. The Poser tool generates human characters with adjustable face, expression, body type, and pose. The Patterns tool creates seamless textures and backgrounds. Collager generates landscape and scene compositions from simple shapes and color fills. Artbreeder has been used to create character concept art, book covers, album artwork, and NPC designs for games. A large library of community-created parent images is free to use and remix. Free plan includes limited monthly creations; paid plans start at $8.99/month. Popular with concept artists, game developers, and digital storytellers who use image blending as a creative tool.

An AI image generation platform specializing in custom fine-tuning, letting users create personalized AI models trained on their own photos or brand assets. The most popular use case is personal portrait generation: users upload 10 to 20 photos of a person and Astria creates a fine-tuned model that generates that specific person in any style, setting, or scenario. This enables professional headshots, product modeling photos, and creative portraits at a fraction of the cost of a photoshoot. Brand teams use Astria to create models trained on their product or mascot for consistent brand image generation across campaigns. The API enables integration into apps and platforms that want to offer personalized AI photo features to their own users. A starter pack including one fine-tune and limited generations costs $9; ongoing plans are credit-based. Popular with individual creators, app developers building portrait features, and marketing agencies.

Google's free web-based AI drawing tool that recognizes rough hand-drawn sketches and suggests polished clip-art equivalents in real time. As a user draws any shape, AutoDraw's machine learning model predicts what the shape is meant to be and shows a row of clean, professionally drawn icons at the top of the screen. Selecting a suggestion replaces the rough sketch with the clean version instantly. AutoDraw is a simple, accessible way for non-artists to create presentable diagrams, notes, visual summaries, and quick illustrations without any drawing skill or design software. The suggestions come from a library of illustrations contributed by professional artists and designers. Available entirely free at autodraw.com with no account required. Popular with teachers creating classroom materials, product managers sketching interface concepts, and anyone who needs quick clean visuals without a design background.

Community platform for sharing and discovering Stable Diffusion models, LoRAs, and AI art resources.