How Onhand and SciSpace differ
| Onhand | SciSpace | |
|---|---|---|
| How you ask | Ask about the paper and Onhand finds the passages that answer it; you can also select text and ask | Highlight text, or clip an equation or table, to get an explanation, then ask follow-ups |
| Showing sources | Highlights the passages on the page, with notes in the margin | A citation with each answer, with the location of the source |
| Finding papers | Follows the citations in the paper you're reading and opens the cited papers | Literature search across 270 million+ papers, and related papers for a highlighted passage |
| What it reads | Any webpage or PDF in Chrome: papers, course pages, docs and articles | Research papers, technical blog posts and reports |
| Saving your work | Sessions saved in your browser with their highlights and notes | Save papers to a SciSpace collection |
| Price and code | Free tier with a daily limit, or your ChatGPT plan or own API key; open source | See SciSpace's website |
SciSpace details are from SciSpace's Chrome Web Store listing as of October 2026. SciSpace is a trademark of its owner; Onhand isn't affiliated with it.
Why read papers with Onhand
- Questions about the whole paper: "What's the main contribution?" or "Where do they define the loss?" Onhand finds the passages and highlights them, so you don't have to know where to look first.
- Citations followed: ask what a reference says, and Onhand opens the cited paper and answers from it.
- Papers compared: with two papers open, ask how they relate, and each claim is highlighted in the paper it came from.
- Learn it, not just skim it: Learning mode asks guiding questions and quizzes you on the paper.
When SciSpace fits better
For literature reviews, SciSpace searches its database of over 270 million papers and finds papers related to a passage. Onhand doesn't search a paper database; it reads the papers you open and the ones they cite.
Using both
Find papers with SciSpace's search, then read each one closely with Onhand.
Try it
Add Onhand to Chrome, open the page you're reading, and click the
Onhand icon or press Ctrl+Shift+Space
(⌘+Shift+Space on a Mac). Onhand Free needs no account
or API key and has a daily limit; you can also sign in with your
ChatGPT plan or use your own OpenAI, Anthropic, Google Gemini or
OpenRouter key.