# Lumen

> Lumen is a reading companion: save articles, highlight and annotate them, ask a model, and send what matters to Obsidian, Notion or markdown. Free and open source.

Lumen is free for personal reading and open source (https://github.com/brgv-code/lumen). Key ideas: highlighting never blocks copy and paste; each collection sends new highlights once to a chosen note (Obsidian, Notion, markdown, webhook); bring your own model (hosted, Ollama, OpenAI compatible, Claude via CLI); agents connect through MCP at https://readwithlumen.app/mcp.

## Product
- Free plan for reading, highlighting and syncing; every new account gets 7 days of Pro (Spark, Radar, agents, analytics, Notion)
- [Changelog](https://readwithlumen.app/changelog)

## Docs
- [Overview](https://readwithlumen.app/docs): What Lumen is and what is in the repo
- [API reference](https://readwithlumen.app/docs/api): Every endpoint, payload and error
- [MCP for agents](https://readwithlumen.app/docs/mcp): Connect Claude, Cursor or any MCP client
- [Extension](https://readwithlumen.app/docs/extension): Toolbar, shortcuts, providers, Claude helper
- [Architecture](https://readwithlumen.app/docs/architecture): System diagram, decisions, flows, security
- [State diagrams](https://readwithlumen.app/docs/states): Lifecycles and the delivery ledger
- [Data model](https://readwithlumen.app/docs/data-model): Tables and relations
- [Run and deploy](https://readwithlumen.app/docs/deploy): Local, Cloudflare, SSO, extension
- [Product plan](https://readwithlumen.app/docs/plan): Problem, principles, scope, roadmap
- [Product audit](https://readwithlumen.app/docs/audit): What was reviewed, fixed, and what is left

## Comparisons
- [Lumen vs Readwise Reader (2026): highlights, notes and where they go](https://readwithlumen.app/compare/lumen-vs-readwise-reader): Readwise Reader is a polished, paid reading app with spaced repetition of highlights and many sources (RSS, newsletters, EPUB). Lumen has a free plan, sends each highlight once to a note you choose (Obsidian, Notion, markdown, webhook), lets you pick the AI model, and plugs into agents through MCP.
- [Lumen vs Glasp (2026): private research highlights or social highlighting?](https://readwithlumen.app/compare/lumen-vs-glasp): Glasp is a free social web highlighter: highlights are shared on a public profile by default and exported as files or copied into notes apps. Lumen is private by default, sends highlights to a chosen note automatically and only once, and adds a reader view, reading plans, analytics and MCP access for agents.
- [Lumen vs Obsidian Web Clipper: highlight, copy and append without duplicates](https://readwithlumen.app/compare/lumen-vs-obsidian-web-clipper): Obsidian Web Clipper is excellent for clipping whole pages into a vault with templates. Its highlighter is a mode that takes over selection, every clip follows the template's fixed destination, and clipping the same page again appends all highlights again. Lumen keeps copy working, lets you pick the target note while reading, appends only new highlights, and works with Notion and markdown too.
- [Lumen vs Hypothesis: personal research notes or open web annotation?](https://readwithlumen.app/compare/lumen-vs-hypothesis): Hypothesis is an open, standards based annotation layer for the web and PDFs, strong for classrooms and group discussion. Lumen is a personal reading tool: private highlights and notes that flow into your own notes app, plus a library, reader view, reading plans and agent access.
- [The best Pocket alternative after the shutdown (2026)](https://readwithlumen.app/compare/pocket-alternative): Mozilla shut Pocket down on July 8, 2025 and closed exports in November 2025. Lumen is a free alternative for saving articles to read later: a clean reader view, inbox to done, highlights and notes, daily reading plans, and export to Obsidian, Notion or plain markdown so you never get locked in again.
- [Omnivore alternative: an open source read later app with highlights (2026)](https://readwithlumen.app/compare/omnivore-alternative): Omnivore, the open source read later app, shut down in November 2024 after its team joined ElevenLabs. Lumen covers the same ground for web reading: save, read in a clean view, highlight with notes, and sync to Obsidian. It is open source, free for personal use, and adds reading plans and agent access through MCP.

## Answers
- [How do I save an article online to read later?](https://readwithlumen.app/answers/how-do-i-save-an-article-to-read-later): Use a read later app: install its browser extension, click save on any article, and read it later in a clean view without ads. Lumen does this for free, keeps your place, and builds a short daily reading plan so saved articles actually get read.
- [What is a read later app?](https://readwithlumen.app/answers/what-is-a-read-later-app): A read later app saves web articles as clean, readable copies in one inbox, so you can read them when you have time instead of keeping dozens of tabs open. Good ones add highlighting, notes, progress tracking and export to your notes app.
- [How do I highlight text on a website and save it?](https://readwithlumen.app/answers/how-to-highlight-text-on-a-website-and-save-it): Install a web highlighter extension such as Lumen, select text on any page, and pick a colour from the toolbar that appears. The highlight is saved with a link back to the exact passage and reappears when you return to the page.
- [Why can't I copy text while highlighting, and how do I fix it?](https://readwithlumen.app/answers/how-to-highlight-and-still-copy-text-in-chrome): Highlighters that work as a mode (such as Obsidian Web Clipper's highlighter) capture every selection, so you cannot copy until you switch the mode off. Use a highlighter that shows a toolbar next to the selection instead; Lumen does this, so Ctrl+C keeps working.
- [How do I send web highlights to Obsidian?](https://readwithlumen.app/answers/how-to-send-web-highlights-to-obsidian): Install Obsidian's Local REST API plugin, add it as an Obsidian destination in Lumen with the note path, and point a collection at it. Every new highlight you make in that collection is appended to the note once, in Obsidian's ==highlight== syntax with a link back to the source.
- [How do I append highlights to an existing Obsidian note instead of creating a new one?](https://readwithlumen.app/answers/how-to-append-highlights-to-an-existing-obsidian-note): Clippers create a new note unless a template says otherwise. In Obsidian Web Clipper, set the template behaviour to append to an existing note. In Lumen, point a collection at the note and pick that collection in the extension; every new highlight is appended there automatically.
- [How do I stop duplicate highlights when I clip the same page twice?](https://readwithlumen.app/answers/how-to-stop-duplicate-highlights-when-clipping): Duplicates happen because the clipper sends every highlight on the page each time. Use a tool that remembers what each note already received. Lumen keeps a delivery ledger per destination, so a highlight is written once, no matter how often you sync or clip.
- [How do I save web highlights to Notion?](https://readwithlumen.app/answers/how-to-save-web-highlights-to-notion): Create a Notion internal integration, share your target page with it, and add the page and token as a Notion destination in Lumen. Point a collection at it; new highlights are appended to the page as quote blocks with a link back to the passage.
- [How do I highlight a PDF in Chrome?](https://readwithlumen.app/answers/how-to-highlight-a-pdf-in-chrome): Chrome's built in PDF viewer is closed to extensions, so web highlighters cannot mark PDFs there. Open the PDF in a viewer that supports annotations: a tool's own PDF viewer, Zotero, or Obsidian with the PDF++ plugin. Lumen's own PDF viewer is in progress.
- [How can I use Claude or another AI agent with my reading list?](https://readwithlumen.app/answers/how-to-use-claude-with-your-reading-list): Connect the agent to Lumen's MCP server. In Lumen press Connect agent, copy the command for Claude Code (claude mcp add) or the config for Claude Desktop or Cursor, and ask things like "what did I read about evals this week, and what should I write next?"
- [How do I turn my reading highlights into blog post ideas?](https://readwithlumen.app/answers/how-to-turn-highlights-into-blog-post-ideas): Collect highlights with a note on why each mattered, then look for passages from different sources that make the same point. That overlap is a post. Lumen's Spark does this automatically: it reads only your highlights and suggests titled ideas with outlines and cited sources.
- [How do I build a reading habit online?](https://readwithlumen.app/answers/how-to-build-a-reading-habit): Make it small and daily: pick one article you started and one short new one, read them in a clean view, and mark them done. A streak helps if it rewards attention (notes, finishing) rather than volume. Lumen's daily reads and glow streak are built around this.