Sidecar | A Classy Nostr Signer

A multi-account NIP-07 Nostr signer with a built-in Lightning wallet, in your browser sidebar.

Sidecar lives in your browser's side panel and hands every Nostr web app a secure window.nostr to sign in with, so you never paste your nsec into a website again. Your keys stay on your device, encrypted behind a PIN. It's a companion to your favorite Nostr client, not a replacement: sign, post, and zap in a tap, then jump right back to the app you love. 🔑 Your keys, your control Full NIP-07 signer: getPublicKey, signEvent, NIP-04 and NIP-44 encrypt/decrypt, and your relay list. Private keys are encrypted at rest (PBKDF2 to AES-GCM via WebCrypto), never stored in plaintext, never transmitted off your device. PIN-protected with automatic re-lock, and a warning before signing anything that would wipe your follows, mutes, or profile. Multiple accounts. Store as many keys as you like, switch the active one in a click, drag to reorder. Each site stays pinned to the account it logged in with, so there's no identity mix-up. Per-site permissions with a prompt that previews exactly what you're signing. Relay sign-in (NIP-42) is answered for your own relays, for reading as well as posting, so relays that gate reads stop coming back empty. Recent activity records what each signature actually was, and any row that signed an event opens it in your client, so the log can be checked rather than taken on trust. 📄 Backups that survive the browser A printable backup sheet for a new key, styled as an old-fashioned telegram: the nsec as text you can copy and as a QR you can scan back in, plus a serial to tell sheets apart. A locked second page carries the key as a password-encrypted secret that passes for a masquerade invitation. Import by photo, PDF, clipboard image, or live camera scan. All generated locally, nothing uploaded. One encrypted vault export covers accounts, wallets, and settings, and restore shows exactly what it will replace. 👤 Your profile, your way View and edit your profile, with the bio editor opening as tall as your bio. Edit and publish your outbox relays (NIP-65) right from your profile. An account overview drawer: following count, relays, NIP-05, Lightning address, wallet status. Follow-list recovery. If another app wipes or shrinks your follows, scan your relays and restore a healthy earlier version. Check your relays: each one carries its own icon, and you can ask whether it is answering, gated behind payment or login, or holding none of your notes, which is the thing worth knowing before you drop it. Your npub as a QR code, with your profile picture in the middle, so handing someone your key does not mean reading out sixty-three characters. ✍️ Post without leaving the page A composer for notes with @mention autocomplete across your follows and all of Nostr, embedded note previews, link cards, and image/video upload to your own Blossom servers. Drafts autosave per account and are encrypted at rest. A short review countdown lets you read the note exactly as it will publish. Post a poll instead of a note, and read the full tally in the panel when the votes come in. Comment on any web page (NIP-22), and keep the bookmark lists your other clients write (NIP-51). 🔔 Notifications at a glance A bell shows replies, mentions, reposts, reactions, and zaps for your active account, each opening in your preferred web client. Reply to a note or a comment without leaving Sidecar. What you are answering stays on screen while you write, through the preview and the review countdown both. Your circle comes first: replies from outside your follows, and their follows, are gathered into a counted group at the bottom rather than mixed in. Nothing is hidden and nothing is deleted. Mute lists written by any client are respected, including muted words, hashtags, threads, and senders. ⚡ Lightning wallet (Nostr Wallet Connect) Connect your own self-custody Lightning wallet over Nostr Wallet Connect. If you don't have one yet, built-in suggestions help you pick. Send (BOLT11 or Lightning address, resolved up front so you see the real recipient), receive with a QR, view history, and back up or export your connection. Pay a Lightning invoice from any page, including one the site copies to the clipboard, plus a WebLN provider with per-site spending budgets you can edit or revoke at any time. Automatic zaps, capped and only on sites you've actually signed into. Podcasting 2.0 boosts, paid from your own wallet, with the show and the message named on the approval. Balance in sats, BTC, or fiat, with a 24-hour price chart. Sidecar never holds your funds. You stay in control of your own wallet. 🎭 Twelve themes A gallery you can filter by dark or light, showing a live preview of each one before you choose it. Six are drawn for low light and six for daylight, each with its own display typeface, textures, and balance animation. A single switch turns the animations off. 🛡️ Private by design Open source. No analytics, no tracking, no remote code. Everything runs locally in your browser, and link previews are fetched with a guard against private-network requests. Tucked into the panel is a small game about relay hops. It runs locally, reaches no network, and keeps nothing but a high score. Works in Chrome, Brave, Edge, and other Chromium browsers. Pin Sidecar, open the side panel, and you're ready. 🍸 🗞️ What's new 1.13.0 • Polls. Ask a question from the composer, set the choices, whether more than one can be picked, and how long it runs. Votes arrive in the bell and open a full tally in the panel: every option with its count and share, who picked which, and the winner once it closes. • Proof of work on your posts, off unless you turn it on and set per account, at 16, 18, 20 or 22 bits. It runs in the background so nothing freezes, and you can stop it. • Replies other clients send as comments now reach you. Many clients answer a note with a comment rather than a note, and everything below the first level of those threads was invisible. • Podcasting 2.0 boosts work. A boost is a keysend rather than an invoice, and the call carrying it was rejected before it ever left the page. The approval names the show and the message instead of a node key. • Set a status: a short line about what you are doing, shown beside your name by clients that read it. • A payment already going out moves to a small indicator in the corner instead of holding the page, and only says it is sending once you have approved it. 1.12.0 • Reply from the notifications list. Answer a note or a comment without leaving Sidecar. The composer opens with what you are answering shown above the editor, and it stays there through Preview and the review countdown. • Fewer strangers in the bell. Reply spam comes from fresh keys, and a mute list cannot outrun those, because a denylist only knows the names it has already been told. Notifications are sorted by who your circle already vouches for instead, with everyone else gathered into a counted group at the bottom rather than hidden, since an allowlist that hides is how you miss the one reply that mattered. • Sidecar can sign in to relays. Some relays gate reading behind a challenge, and Sidecar had no way to answer it, so those relays served the panel nothing at all. It answers now, for reading as well as posting, and only for your own relays. • Zap notifications say how much, far more often. The amount was read from a tag that many wallets leave out. It now falls back to the invoice, where the number was all along. • Recent activity can be checked rather than taken on trust. Every signature records the id of what it signed, and a row that has one opens that event in your preferred client. The log used to record that something was signed and never what. • Relays and signing got more reliable. Connections were not being released, so eventually every relay reported a timeout while those same relays answered fine outside the browser, and only restarting helped; a Reset connections button now rebuilds them if it ever happens again. A signing request could also arrive with no prompt and no error, and a relay lookup that timed out could leave you posting to Sidecar's defaults instead of your own relays. All three are fixed.