RedPen

What it does

RedPen provides high-quality solutions to exams and exercises. It captures entire exams of up to 20 pages, identifies the main exercises, and produces detailed, step-by-step explanations tailored to the user’s level. The feature we are most proud of is exam cloning: by generating new exams tailored to a user’s specifications based on previously solved exams, we help students prepare with an infinite number of practice exercises.

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  Brill 2.02019 · brill.app · ▲241

  From sticky notes to anywhere 200x faster than typing

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  Render Jupyter notebooks as interactive articles2021 · deepnote.com · ▲217

  Notebooks for data scientists and data analysts.

• TM
  TubePen – My attempt to get more out of YouTube learning2025 · tubepen.com · ▲74

  Hi HN! I made this because I always forget what I'm trying to learn from YouTube. Test yourself: Can you remember the main concepts from the last (educational) video you watched? So, why not highlight and take notes on YouTube videos, just like in books? That's TubePen. Sign in, replace "youtube" with "tubepen" in your YouTube URL, and you're ready to retain more from your videos. I’d love your feedback! What do you think of my landing page? Use the 10-day free trial and see if it’s useful for you. Thanks!

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  Synap2023 · synap.ac · ▲53

  Scalable, secure and seamless online exams

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  Notes Keeper2021 · play.google.com · ▲32

  Create notes, memos and to-do lists in no time

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  Noteless - A Markdown-based note-taking app for Android2020 · github.com · ▲34

  A Markdown-based note-taking app for mobile devices. - redsolver/noteless

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  zCAD AI▲321

  AI 3D that creates real parts, not just shapes

  Work · 12d ago · zcad.ai

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  Lofi Cities – Pixel-art city nights with browser-generated lofi▲319

  Endless lofi beats composed live in your browser, over pixel-art nights in Paris, Tokyo, New York, Hong Kong, Sydney, San Francisco and more. Free, no sign-up.

  Work · 30d ago · loficities.com

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  Smooth Recorder▲257

  Mac screen recordings that look edited when you hit stop

  Work · 24d ago · smoothrecorder.com

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  Badgey▲226

  Your iPhone becomes a name badge that faces the room

  Work · 19d ago · apps.marcoluthi.com

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  Figma Specs▲225

  A container for your context that lives on the Figma canvas

  Work · 9d ago · figma.com

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  The rarest tech books and docs you've probably never read▲190

  Work · 18d ago · readrare.com

• IN
  isometric.nyc – giant isometric pixel art map of NYC▲1,325

  Hey HN! I wanted to share something I built over the last few weeks: isometric.nyc is a massive isometric pixel art map of NYC, built with nano banana and coding agents. I didn't write a single line of code. Of course no-code doesn't mean no-engineering. This project took a lot more manual labor than I'd hoped! I wrote a deep dive on the workflow and some thoughts about the future of AI coding and creativity: http://cannoneyed.com/projects/isometric-nyc

  AI · Jan 2026 · cannoneyed.com

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  Cowork▲1,088

  Turn Claude into your digital coworker

  AI · Jan 2026 · claude.com

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  DataFast▲867

  Revenue-first analytics

  Growth · Jan 2026 · datafa.st

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  OpenClaw▲836

  The AI that actually does things

  AI · Jan 2026 · openclaw.ai

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  Kilo Code Reviewer▲799

  Automatic AI-powered code reviews the moment you open a PR

  Dev tools · Jan 2026 · kilo.ai

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  PostSyncer▲793

  AI Content Maker, for Social Media Publishing

  AI · Jan 2026 · postsyncer.com