# Omphalis > Omphalis turns anything you read, watch, or listen to (articles, PDFs, podcasts, videos) into a clean, structured, understandable piece you can return to. It is built around comprehension, not summarization: content is cleaned, then structured into typed moments (Strata), then annotated with high-precision explanations (Marks), and connected to what you have kept before. Omphalis is a source-first personal knowledge and comprehension tool. It does not replace reading with a generated summary; it helps you read, listen to, and understand the actual source, and keeps a path back to the parts that mattered. Value arrives in four layers: **Clean** (per-format extraction that turns any source into the same calm, readable page), **Structure** (Strata: the typed moments that show a piece's shape), **Mark** (high-precision annotations on the parts that are genuinely hard), and **Connection** (what a new piece has to do with what you already kept). Every page below is also available as Markdown: append `.md` to any URL, or request the URL with `Accept: text/markdown`. Agent-facing metadata lives at /.well-known/api-catalog, and the API and MCP server are documented at /auth.md. ## Product - [A place to read and work with your sources](https://omphalis.ai/product/web-app): Bring an article, PDF, podcast, or video into Omphalis. Read with explanations, take notes, ask questions, and keep related sources in notebooks. - [Browser extension for Chrome and Firefox](https://omphalis.ai/product/browser-extension): Save an article from your browser or open it in a clean reading view, with a section map, inline explanations, and Listen. - [Build a course from real sources](https://omphalis.ai/product/course-builder): Choose what you want to learn, review a course plan, and work through lessons drawn from real sources with their attribution. - [See it](https://omphalis.ai/demo): A live demo on a real article, podcast, and video: the structure surfaced, the hard parts explained, and the audio following the text word by word. - [Pricing: Free, Pro, Premium, and Scholar plans](https://omphalis.ai/pricing): Free, Pro $9/mo, Premium $19/mo, Scholar $39/mo. Founding members get 90 days of full Premium. We never paywall your own thinking. ## What it reads - [Read podcast transcripts with explanations](https://omphalis.ai/read/podcasts): Add an episode and open its transcript. Move to a section, reread what the speaker said, and open an explanation of an unfamiliar name or idea without leaving the passage. - [Read YouTube talks with explanations and notes](https://omphalis.ai/read/youtube): Paste a YouTube link and read the talk as a transcript. Pause over a difficult explanation, check an unfamiliar term, and leave a note on the part you want to use later. - [Read PDFs with explanations and notes](https://omphalis.ai/read/pdf): Upload a report or paper and work through its text in the reader. Use the section map to move around, open an explanation when you need one, and write a note beside the passage. - [Read and understand research papers](https://omphalis.ai/research-papers): Upload a paper as a PDF. Read the extracted text, open an explanation when a term stops you, and leave a note on the passage you want to discuss. You can also listen in a natural voice. - [Help with difficult reading](https://omphalis.ai/reading-comprehension): Bring the article, paper, or PDF you are working through. Open an explanation beside a difficult passage, go back to the author’s words, and write down what you now understand. - [Ask questions about your reading, with citations](https://omphalis.ai/ask): Open Ask when you want to test your understanding or find an idea again. Answers draw on your saved sources and include citations you can follow back to the reading. ## Moving from another tool - [A home for your Pocket reading list](https://omphalis.ai/pocket): If you kept a Pocket export, you can import it into Omphalis and start with an article you still want to read. Open the text, get help with a difficult passage, and leave your own notes beside it. - [Save articles, read them, and keep your notes](https://omphalis.ai/read-later): Save a piece you want to spend time with. Open a clean reading view, get help with a difficult passage, and keep a note about why it interested you. Choose Listen when you want natural-voice narration. - [Compare Omphalis, Heptabase, Readwise and NotebookLM](https://omphalis.ai/compare): Compare reading, questions and notes in Omphalis, Heptabase, Readwise Reader, NotebookLM, Obsidian and other tools. Practical differences with official sources. - [Readwise alternative: Omphalis vs Readwise Reader](https://omphalis.ai/vs/readwise): Readwise Reader and Omphalis both offer reading, questions and listening. Compare how each helps with a difficult passage and the notes you keep. - [NotebookLM alternative: Omphalis vs NotebookLM](https://omphalis.ai/vs/notebooklm): Compare source questions, reading, notebooks and listening in NotebookLM and Omphalis, with real Omphalis examples and official Google documentation. - [Heptabase alternative: Omphalis vs Heptabase](https://omphalis.ai/vs/heptabase): Compare Heptabase's cards, whiteboards and source questions with reading, explanations, narration and notebooks in Omphalis. Real examples and official sources. ## Thinking behind it - [The case for comprehension](https://omphalis.ai/the-case-for-comprehension): Why Omphalis is built around comprehension rather than summarization, and what cognitive science says about how understanding actually works. - [The Omphalis manifesto: build for understanding](https://omphalis.ai/manifesto): The choices behind Omphalis: help with difficult reading, explanations you can check, notes with their sources, and control over what you keep. - [About: why we built Omphalis](https://omphalis.ai/about): Why Stanly Thomas built Omphalis to help him stay with what he reads, and where the name comes from. - [Common questions and answers](https://omphalis.ai/faq): Answers about reading, Ask, notebooks, supported sources, pricing, privacy and export in Omphalis. ## Company and policies - [Press](https://omphalis.ai/press): Where Omphalis has appeared, and how to reach us for press inquiries. Coverage of the reading and comprehension platform built by Voxiven LLC. - [Security, encryption, and your data](https://omphalis.ai/security): How Omphalis stores and processes your content, what you can control, and where to find the full privacy and retention terms. - [Privacy and your data](https://omphalis.ai/privacy): How Omphalis handles your data, in plain English and in legal terms: what we collect, why, how long we keep it, and the rights you can exercise. - [Terms of service and acceptable use](https://omphalis.ai/terms): The terms of service for Omphalis: the agreement covering acceptable use, your subscription and billing, ownership of your content, and your rights as a user. - [Disclosures](https://omphalis.ai/disclosures): How Omphalis makes money, and what could bias anything written on this site: affiliate links, sponsorships, reviews, and how the comparison pages are written. - [Accessibility](https://omphalis.ai/accessibility): Omphalis and accessibility: the standard we aim for (WCAG 2.2 Level AA), what we do to meet it, what is not covered yet, and how to report a problem. - [Delete your account](https://omphalis.ai/delete-account): How to permanently delete your Omphalis account and everything in it: what gets removed, what happens to your data, and how to start the process. - [Contact: questions, press, and partnerships](https://omphalis.ai/contact): Reach out to the Omphalis team. We answer questions about the product, press and media inquiries, partnership proposals, and privacy or data requests. ## Blog - [Blog: notes on reading and understanding](https://omphalis.ai/blog): Notes on reading, comprehension, and the tools that help you return to what you keep. - [The Best AI Note-Taking Apps, Compared by What They Actually Preserve](https://omphalis.ai/blog/best-ai-note-taking-apps-compared-by-what-they-actually-preserve): A comparison of AI note-taking apps and tools based on what they preserve: raw text, summaries, annotations, transcripts, and connections. - [Matter Review: Is It Good for Saving and Revisiting Articles?](https://omphalis.ai/blog/matter-review-is-it-good-for-saving-and-revisiting-articles): See if Matter is the right read-it-later app for your research backlog. We test its saving, highlighting, and revisiting features across Apple devices. - [Annotation that survives the article it came from](https://omphalis.ai/blog/annotation-that-survives-the-article-it-came-from): Annotations are more than highlights. They capture your interpretation, questions, and the threads you plan to follow. - [ChatGPT Can Summarize a Paper. It Can't Read It for You.](https://omphalis.ai/blog/chatgpt-can-summarize-a-paper-it-cant-read-it-for-you): ChatGPT can summarize a research paper in seconds, but a summary is not reading: keep the structure, marks, and path that make understanding returnable. - [The Second Brain Trap: Why Most Knowledge Apps Become Digital Hoarding](https://omphalis.ai/blog/the-second-brain-trap-why-most-knowledge-apps-become-digital-hoarding): Why second-brain apps turn into digital hoarding, and how fewer saves with marks and a path back restore comprehension. - [Are AI Summaries Killing Deep Reading? Here's What the Science Says](https://omphalis.ai/blog/ai-summaries-killing-deep-reading): AI summaries can orient you, but recent research suggests that letting them replace reading produces shallower knowledge: here is a better reading loop. - [How to Read a PDF with AI Without Losing the Plot](https://omphalis.ai/blog/how-to-read-a-pdf-with-ai-without-losing-the-plot): Map a dense PDF, mark the moments that matter, and keep a way back instead of collapsing it into a summary. - [7 Mistakes You're Making with AI Note-Taking Apps (and How to Fix Them)](https://omphalis.ai/blog/7-mistakes-youre-making-with-ai-note-taking-apps): Where AI note-taking apps create the appearance of understanding, and how to keep capture from replacing reading. - [A Literature Review Workflow That Doesn't Turn Into a Pile of Tabs](https://omphalis.ai/blog/a-literature-review-workflow-that-doesnt-turn-into-a-pile-of-tabs): A save, read, mark, and connect loop for literature reviews so papers stop piling up as unread tabs. - [Notes from audio: why listening leaves less behind than reading](https://omphalis.ai/blog/notes-from-audio-why-listening-leaves-less-behind-than-reading): Today many people turn to listening as a main way to consume information. The question remains practical for readers: does listening leave less behind - [What to do with a two hour talk you only need twenty minutes of](https://omphalis.ai/blog/what-to-do-with-a-two-hour-talk-you-only-need-twenty-minutes-of): You’ve sat through a two hour talk and left with a single takeaway that would fit into a twenty minute slot. The question isn’t how to trim the talk, but how - [Keeping a literature review from turning into a pile of tabs](https://omphalis.ai/blog/keeping-a-literature-review-from-turning-into-a-pile-of-tabs): A literature review stays usable when sources land in one navigable map. Build a core library, chart how studies connect, and keep the narrative current. - [Reading a PDF that was never designed to be read on screen](https://omphalis.ai/blog/reading-a-pdf-that-was-never-designed-to-be-read-on-screen): Many PDFs resemble print documents repurposed for screens, which can make it hard to maintain your place, see content as pages render, and scan long sections. - [Open source and self hosted knowledge tools, and what you trade for control](https://omphalis.ai/blog/open-source-and-self-hosted-knowledge-tools-and-what-you-trade-for-control): Open source knowledge tools give you visibility into the software you run. You can inspect, modify, and tailor the system to your workflows without waiting - [Obsidian and the limits of a folder of notes](https://omphalis.ai/blog/obsidian-and-the-limits-of-a-folder-of-notes): Obsidian centers on how ideas connect, not just where you file them. Folders offer a familiar boundary, but the real strength lies in spotting relationships - [What a personal knowledge management system is actually supposed to do](https://omphalis.ai/blog/what-a-personal-knowledge-management-system-is-actually-supposed-to-do): You already read a lot. You want to remember more of it and turn what you read into things you can act on. A personal knowledge management system is not - [Choosing a personal knowledge management app you will still use in a year](https://omphalis.ai/blog/choosing-a-personal-knowledge-management-app-you-will-still-use-in-a-year): Choosing a personal knowledge management app you will still use in a year is about long term viability, not just features today. - [Getting more out of a podcast than you would from listening once](https://omphalis.ai/blog/getting-more-out-of-a-podcast-than-you-would-from-listening-once): At Omphalis, a podcast is more than a single listening event. It becomes a starting point for deeper understanding and a seed for a structured knowledge map - [How to actually finish the research papers you save](https://omphalis.ai/blog/how-to-actually-finish-the-research-papers-you-save): Start with a full audit of what you have: writings, data, and readings. This is the essential precondition for finishing a PhD or any research paper. - [What a personal knowledge library is for once it stops being a backlog](https://omphalis.ai/blog/what-a-personal-knowledge-library-is-for-once-it-stops-being-a-backlog): You built a personal knowledge base to move beyond a growing backlog. The goal is not to capture more for its own sake, but to connect ideas, support - [How structure changes what you retain from a long article](https://omphalis.ai/blog/how-structure-changes-what-you-retain-from-a-long-article): Structure does more than organize content. It shapes how you process, store, and retrieve ideas. When information is arranged with clear boundaries - [Best Read-Later Apps That Actually Help You Finish What You Save (2026)](https://omphalis.ai/blog/best-read-later-apps-that-actually-help-you-finish-what-you-save-2026): Discover the top read-later apps designed for researchers, students, and knowledge workers to efficiently manage and finish their saved content in 2026. - [Hello from Omphalis](https://omphalis.ai/blog/hello-from-omphalis): Omphalis is a home for what you choose to keep: articles, podcasts, talks, and voice notes, structured so you can actually return to them later.