AI Writing Assistant — Improve Any Text, in Any App, Instantly

Most AI writing tools make you go to them. You copy your text, open a browser tab, paste it in, prompt the AI, copy the result, and paste it back. Lightning Assist is an AI writing assistant that works the other way around — select text in any desktop app, press a hotkey, and the improved version appears in place. No tab switching, no copy-pasting, no workflow interruption.

AI Writing Assistant — 14-Day Free Trial

Rewrite • Fix grammar • Adjust tone • Translate • Any app • No credit card

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How It Works

Lightning Assist runs in the background on your desktop. When you want to improve something you've written:

  1. Select the text you want to improve — anywhere on your desktop
  2. Press the AI hotkey (Ctrl+Shift+A on Windows, ⌘+Shift+A on Mac)
  3. Choose a command — Rewrite, Make professional, Make concise, Fix grammar, Translate, or a custom prompt
  4. Done — the improved text replaces your selection instantly

The whole interaction takes under 5 seconds. No app switching, no copy-pasting, no prompt engineering.

Built-In AI Writing Commands

Rewrite for Clarity

Transform rough drafts into polished text. Select a paragraph you wrote quickly and get a cleaner, clearer version without changing the core meaning.

Adjust Tone

Make text more professional, more casual, more empathetic, or more direct. Useful for support replies, client emails, or internal messages that need a different register.

Make It Concise

Shorten without losing meaning. Select a long paragraph, press the hotkey, and get a tighter version — useful for Slack messages, email previews, or social posts.

Fix Grammar & Style

Catch grammar errors, awkward phrasing, and inconsistent style. Works in any application — including ones that Grammarly doesn't support, like desktop email clients, terminals, or proprietary tools.

Translate

Translate selected text into any language inline, without opening a translation tool or browser tab.

Custom Prompts

Create your own AI writing commands — "Rewrite as a formal business email", "Summarise in 3 bullet points", "Make this sound like a status update" — and trigger them with a dedicated hotkey.

Works in Every App Where You Type

Because Lightning Assist is a native desktop app (not a browser extension), AI writing commands work system-wide:

  • Email — Outlook, Thunderbird, Apple Mail, Gmail in browser
  • Documents — Word, Google Docs, Notion, Confluence, Pages
  • Chat & messaging — Slack, Microsoft Teams, Discord, Telegram desktop
  • Customer support — Zendesk, Intercom, Freshdesk, HubSpot
  • Code editors — VS Code, JetBrains IDEs, Sublime Text (for comments and docs)
  • Any other app — if you can type in it, AI commands work in it

AI Writing Assistant + Text Expander in One Tool

Lightning Assist combines two things most professionals need daily:

Text expansion — create snippets for text you type repeatedly (email templates, canned replies, signatures, code blocks) and expand them with a short trigger. Saves time on fixed, repetitive content.

AI writing commands — improve text you've already written on the fly. Useful when the content varies but the quality standard needs to stay consistent.

You can also combine them: expand a snippet, then select the result and run an AI command to adapt the tone for a specific context. One tool, both workflows.

Updated for 2026: Related guides

How It Works

The whole interaction takes under 5 seconds. No app switching, no copy-pasting, no prompt engineering.

Lightning Assist combines two things most professionals need daily:

Try the AI Writing Assistant

14-day free trial, all features included, no credit card required. Windows, Mac & Linux.

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Frequently Asked Questions

What is an AI writing assistant?

An AI writing assistant helps you write better, faster text by rewriting, improving, shortening, or adjusting the tone of what you've already written. Unlike a blank chatbot, a writing assistant works on your existing text — you write a draft, select it, and the AI improves it in place.

How does Lightning Assist work as an AI writing assistant?

Select any text in any desktop application — an email, a Slack message, a support reply, a document — press the AI hotkey, and choose a command: Rewrite, Make professional, Make concise, Fix grammar, Translate, or a custom prompt. The improved version replaces your selected text instantly, without leaving the app.

Does it work in every app, or only specific ones?

Every app. Lightning Assist is a native desktop app that intercepts text system-wide. AI writing commands work in Outlook, Gmail, Slack, Teams, Word, Google Docs, Notion, Zendesk, Intercom, VS Code, and any other application where you type on Windows, Mac, or Linux.

How is this different from using ChatGPT or Grammarly?

ChatGPT requires switching to a browser tab, pasting your text, prompting, and copying the result back — slow for everyday writing. Grammarly only fixes grammar and works in limited apps. Lightning Assist AI commands work inline in any application (including ones Grammarly doesn't support), cover both grammar and full rewrites, and operate with a single hotkey press.

Can I create custom AI writing commands?

Yes. In addition to built-in commands (rewrite, shorten, translate, adjust tone), you can create custom AI prompts — for example "Rewrite this as a formal business email" or "Summarise this in 3 bullet points" — and trigger them with a dedicated hotkey.

Is there a free trial?

Yes. Lightning Assist offers a 14-day free trial with all features included — AI commands, text expansion, speech-to-text, and team sharing. No credit card required. Available for Windows, Mac, and Linux.

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