Explainpaper is great at highlight-to-explain on a paper you upload. Sidenote does that in the browser on arXiv and live PDFs - and adds chat, a one-click glossary, and citations that scroll the PDF to the source.
For Research Papers
Understand any research paper - with the citations to prove it.
Sidenote is a browser extension (Chrome, Edge and Firefox) that reads the paper you have open (arXiv, a journal PDF, or one you upload) and helps you get through it: plain-English explanations, a glossary of the jargon, and chat. Every answer cites the paper and scrolls you to the exact line.
Works on arXiv, journal PDFs & uploads · OCR for scanned papers
Sidenote
Scaling laws for retrieval
We study how retrieval-augmented models scale with corpus size and index width, holding the parameter budget fixed. Our headline finding is that doubling the retrieved context cut perplexity by 11% at fixed compute, a consistent gain across every configuration. We note one caveat: returns diminish sharply past sixteen passages, so the trend should not be extrapolated to very wide indexes.
Sidenote · What is the headline result?
Doubling the retrieved context cut perplexity by 11% at fixed compute 1 - though the authors caution that returns diminish past sixteen passages 2.
The problem
Papers are dense on purpose. You still have to read them.
Undefined notation, acronyms three sub-fields deep, a methods section written for the four people who already know it. Most AI tools will happily summarize a paper, and just as happily invent a result it never claimed.
Sidenote is built for trust: it explains and summarizes, but every claim is pinned to a passage you can jump to and check. The paper stays the source of truth.
How it works
How Sidenote works on a paper.
STEP 01
Open a paper - or drop one in.
Works on arXiv pages and PDFs your browser can open, with nothing to upload. For a paper that isn't online, drag the PDF onto the side panel; scanned PDFs get OCR'd first.
STEP 02
Ask, simplify, or build a glossary.
Ask a question, highlight a dense passage for a plain-English rewrite, or one-click a glossary of every acronym and term in the paper.
STEP 03
Click a citation, land on the line.
Every answer is grounded in a quoted passage. Click the chip and Sidenote scrolls the PDF to the exact sentence and highlights it in amber.
Reviewing a stack of papers? Bundle them into a collection and ask one question across all of them - every citation names its paper. Just after the gist before committing to a full read? See the AI summarizer.
Use cases
Get through the paper, not just the abstract.
“Explain this paragraph in plain English.”
Highlight a dense passage and Sidenote rewrites it in plain language - without losing the meaning, and with the original still one click away.
“What do all these acronyms mean?”
One click builds a glossary of every term and acronym in the paper, each entry linked to where it's first defined.
“What did they actually do, and on what data?”
Sidenote summarizes the method and dataset and cites the exact lines, so you can judge the work, not just the abstract's spin.
“Where does it say that?”
Every answer carries a citation. Click it and Sidenote scrolls the PDF to the exact sentence and highlights it.
“How do these three papers compare?”
Bundle a set of papers into a collection and ask synthesizing questions across them. Each citation names the paper it came from.
“Is this relevant to my work?”
Get a grounded summary of the contribution and limitations before you commit an afternoon to the full read.
Compared
Sidenote vs the academic AI tools.
The dedicated paper tools are good. Sidenote's difference is that it rides along in the browser you already read in, works beyond academia too, and pins every answer to a passage you can jump to.
SciSpace is a full research platform you bring papers into. Sidenote is a lightweight per-user reader that travels with you, across papers and the rest of the web, and grounds every answer in a citation you can verify.
FAQ
Common questions about reading papers with Sidenote.
Try it on a paper
Read the paper. Trust the answer.
Add Sidenote to your browser, open an arXiv paper or a PDF, and ask it anything. Free tier forever, opt-in 7-day Pro trial, no card required.
Works on arXiv, journal PDFs, and uploads · OCR for scanned papers