Toastr is a decentralized Nostr app that lets you comment on any website, using the Nostr protocol. Toastr is available at toastr.net - it's also available as a browser extension here. The browser extension functions identically to the website, but lets you instantly click the extension to see toasts for the page you're currently on. The icon lights up automatically when you're on a website that people have already toasted.

For privacy reasons, Toastr scrapes all known toasts from the relays you're connected to, stores them in your browser, and then filters based on the exact domain/URL you're looking at to avoid leaking search queries or your browser history.

A toast is defined as a kind 1 event, with tags ['r', <URL>], ['t', 'toastr'], ['subject', <subject>]. Due to limitations in the Nostr protocol, all toasts must be explicitly tagged toastr at this time. Responses to toasts are currently implemented as standard kind 1 events.

Toastr implements NIP-07. However, browser extensions cannot interact with other browser extensions, so the extension version of Toastr requires your nsec / preferred nostr relays in order to work. This limitation does not apply to the web version, which is compatible with extensions like nos2x.