How it works
- 1
Paste two lines
- 2
Pick a language and a level on the first run
- 3
Carry on working as usual
Watch it happen
One ordinary conversation, start to finish. Nothing to install to see it.
- 1You type something
- 2Claude answers as usual
- 3One expression lands at the end
Inside the conversation
No drilling boring flashcards
You learn from context, the way a conversation naturally works.
And any other language Claude knows.I need to tell a customer her order is running late. Draft me something short.
I need to tell a customer her order is running late. Draft me something short.
I need to tell a customer her order is running late. Draft me something short.
I need to tell a customer her order is running late. Draft me something short.
I need to tell a customer her order is running late. Draft me something short.
I need to tell a customer her order is running late. Draft me something short.
No account, no server
Your progress is stored on your machine
Sidenote has no external server or telemetry. Your profile and expressions retrieved for practice are shared with Claude as part of the conversation, under your Claude privacy settings.
{
"target": "en",
"level": "B2",
"learned": [
{ "expression": "to give someone a heads-up",
"on": "2026-09-24" },
{ "expression": "to get it out of the way",
"on": "2026-09-27" }
]
}
What you get
- A new expression with each answerTied to what you just did
- Remembers what you learnedNever teaches the same one twice
- Any languageSpanish, French, Japanese and more
- At your levelFrom A2 to C1
- FreeOn the Claude plan you already have
- Stays with youOne file, no account
| Sidenote | Browser extensions | Flashcard apps | |
|---|---|---|---|
| Where the words come from | The answer you just read | Random words on whatever page you opened | A list somebody else wrote |
| What you have to open | Nothing. It is already inside Claude Code | A browser, with the extension on | The app, every day |
| Where your progress lives | One file on your disk: ~/.sidenote/state.json | Their server, behind an account | Their server, behind an account |
| What it costs | Nothing. It runs on the Claude subscription you already pay for | Free, then a subscription | A few dollars a month |
You don't have to trust us. You can check.
An automated check verifies that the local server uses no network APIs, external dependencies or hooks.
- One fileAbout 500 lines you can read
- Zero dependenciesNo one else's libraries
- No networkThe code never contacts a server
Or ask Claude to check it for you:
Fair questions
Does it slow me down?
No. The answer you asked for stays complete and comes first. The expression follows it, in one line.
Do I need an account?
None. No signup, no email, no personal URL. Install and start.
What does it cost?
Nothing. The plugin runs on the Claude subscription you already have.
Where is my progress stored?
In one file on your own machine, at ~/.sidenote/state.json. Sidenote has no external server or telemetry. Your profile and expressions retrieved for practice are shared with Claude as part of the conversation, under your Claude privacy settings.
Which languages?
Any language Claude knows. Spanish, French, Italian, German, Portuguese, Japanese, Hebrew, Arabic, Russian and more.
How do I remove it completely?
claude plugin uninstall sidenote, then delete the folder. That is all.
I stopped for a month. What happens?
Nothing is lost. The file stays where it is and the expressions wait. They do not pile up into a debt of two hundred reviews waiting for you on the day you come back. You pick up where you left off.
How do I get new expressions and improvements?
Turn on automatic updates: in Claude Code, type /plugin, open Marketplaces, pick sidenote and choose Enable auto-update. Or now and then: claude plugin update sidenote@sidenote.
Does this site measure anything?
Yes, the minimum. A plain counter adds one each time the page opens or the install command is copied. A number only, and no cookie. The plugin on your computer is a separate thing. Progress is stored locally; tool results are shared with Claude in the conversation.
Learn fast, without the effort
Two lines. Once.