Riff

Riff is a free Chrome extension that drafts replies, direct messages and original posts for X, LinkedIn, Facebook and Instagram. It runs on Gemini Nano, the language model built into Chrome, so text is generated on the user's own computer. Zima Media OÜ makes it and states it has no affiliation with Google, X, LinkedIn or Meta. It is built for people who reply and post on social media, including to promote a service or brand.

Riff opens in Chrome's side panel from the toolbar or a keyboard shortcut. The user picks a post or chat, pastes a rough point and sets the dials, then presses Enter. Gemini Nano reads the post or conversation, writes a draft, checks it against length limits, a never-say list and the user's last 60 replies, then tidies it. Riff fills the reply box but never sends; the user presses send.

Dials control intelligence, pitch strength, sales tactic, spin, tone, length, emoji, language and link placement, and each draft follows the current site's character limit and style. In post mode, rough notes become a LinkedIn post, an X thread or an Instagram caption, with three hook options, saved versions and repurposing between sites. Brand voices, saved points, a link library and presets stay on the device. The manual also covers X Chat, Slack and Microsoft Teams.

Riff costs nothing and needs no account, subscription or API key. It requires desktop Chrome 138 or newer on Windows, Mac, Linux or Chromebook Plus and a one-time Gemini Nano download, after which it works offline. It writes in the post's own language or in English, Spanish, French, German or Japanese. It does not yet work on messenger.com, and on unsupported sites the text has to be pasted into the panel.