How Onhand and Sidenote differ
| Onhand | Sidenote | |
|---|---|---|
| Showing the source | Highlights the passages it used on the page as it answers, with a note in the margin beside each | Citation chips in the side panel; click one and the page scrolls to the sentence and highlights it |
| Where it runs | A Chrome side panel, with its own PDF viewer | A side panel in Chrome, Edge and Firefox, plus desktop apps and a web dashboard |
| What it reads | Webpages and PDFs, online or on your computer, and clearly related open tabs | Webpages, PDFs, YouTube and email, connected Google Docs, Notion and Confluence, and uploaded files such as Word and PowerPoint |
| Learning | Learning mode: guiding questions, hints and quizzes tied to the page; flashcards and summaries when you ask | Summaries, explanations at a chosen reading level and a glossary; flashcards and quizzes on paid plans |
| AI models | Onhand Free, your ChatGPT plan, or your own OpenAI, Anthropic, Google Gemini or OpenRouter key | Anthropic's Claude models, chosen by Sidenote |
| Account and data | No account for Onhand Free; saved sessions stay on your device | Email sign-in; documents are processed and stored on Sidenote's servers unless you choose to discard them |
| Price and code | Free tier with a daily limit, or your ChatGPT plan or own API key; open source under Apache 2.0 | A free plan with monthly limits and paid plans; see Sidenote's website |
Sidenote details are from Sidenote's website and Chrome Web Store listing as of October 2026. Sidenote is a trademark of its owner; Onhand isn't affiliated with it.
Built for the page you're reading
- Evidence without clicking: the passages behind an answer light up on the page while Onhand answers, so you can check each point where it's written.
- Notes in the margin: a sentence or two beside each highlight, so you keep your place on the page.
- Citations followed: ask what a reference like [14] says, and Onhand opens the cited paper and answers from it.
- A tutor when you want one: Learning mode asks before it tells and quizzes you on the page.
When Sidenote fits better
Sidenote reaches more places. Its connectors read Google Docs, Notion and Confluence, and it works with Gmail and Outlook, YouTube videos with timestamped citations, Word and PowerPoint uploads, and scanned PDFs with OCR on paid plans. It also keeps a searchable library you can ask across, runs in Firefox and as a desktop app, and offers team plans. If you work mostly in those tools, Sidenote covers them; Onhand is focused on the webpages and PDFs you read in Chrome.
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.