A calmer place to think.
Lumen turns a blank page into a conversation. Draft, debug, and decide, with answers that stay organized and clear.
Everything you need to think out loud
Threads that remember
Every conversation is saved and organized. Pick up where you left off, rename threads, and keep your work in one place.
Reads like a document
Answers render as clean Markdown, with syntax-highlighted code and typeset math. Long replies stay readable.
Shows its thinking
When a model reasons through a problem, Lumen displays that reasoning inline so you can follow the logic.
Keeps the momentum
Lumen suggests useful follow-up questions after a reply, so a good answer leads to the next one.
Built on frontier models
Your messages route to current, capable models. You get strong answers without picking a provider yourself.
Yours and protected
Your account and conversations sit behind authentication. You sign in, and your history stays with you.
Made for the way you work
Writing
Draft emails, essays, and posts. Lumen helps you find the words, then tighten them.
Coding
Debug, refactor, and learn. Answers arrive with syntax highlighting you can read.
Studying
Turn dense material into clear explanations, summaries, and practice questions.
Planning
Think through decisions, break down projects, and keep the thread for later.
From sign in to answer in under a minute
- 01
Sign in
Create an account in seconds. No install, no setup. Lumen runs in your browser.
- 02
Start a thread
Ask a question, paste some code, or think out loud. Lumen replies with clean, readable formatting.
- 03
Keep going
Your threads save automatically. Come back anytime and continue the conversation.
On the roadmap
- Files and documents you can ask questions about
- Tools and MCP connections
- Team workspaces
Questions, answered
- What is Lumen?
- Lumen is an AI assistant for everyday thinking, writing, and coding. You chat in threads that save automatically, and Lumen replies with clean formatting for text, code, and math.
- Which AI models does Lumen use?
- Lumen runs on current frontier models and routes your messages to a strong default, so you do not have to choose a provider. Pro unlocks priority access and longer context.
- Is my data private?
- Your account and conversations sit behind authentication and stay tied to your account. Lumen does not sell your data.
- Can I use Lumen for coding?
- Yes. Code blocks render with syntax highlighting, and Lumen keeps long, technical answers readable. It is a capable coding companion.
- How much does Lumen cost?
- Lumen has a free tier and a Pro plan at $18 per month. The free tier covers everyday use, and Pro adds higher limits and priority model access.
- Do I need to install anything?
- No. Lumen runs in your browser. You sign in and start a conversation. There is nothing to download.
Start a conversation with Lumen.
Free to try. Your threads save automatically, so you can pick up right where you left off.