ThunderAI

ThunderAI brings AI writing and email processing into Thunderbird for people who want help with their inbox while choosing where their messages go. It can use local models through Ollama or an OpenAI-compatible server such as LM Studio. Cloud connections send the selected content to ChatGPT, the OpenAI API, Google Gemini or Claude instead.

It drafts replies, corrects spelling and grammar, rewrites text in a chosen tone, and translates or summarizes messages. Proofreading includes a side-by-side change picker, so you can accept individual suggestions or edit them yourself. Rewrites preserve HTML formatting, and summaries can cover several emails at once.

For inbox organization, ThunderAI can suggest and assign Thunderbird tags or classify messages using your own criteria. API integrations also support automatic tagging, spam filtering, summaries and inline translations for incoming mail. These automatic actions skip drafts, templates, outbox and sent messages.

Custom prompts let you adapt the assistant to your own correspondence. You can share prompts through import and export, add reusable data placeholders, and choose a different provider or model for each prompt. Batch processing applies a prompt to multiple emails. The companion ThunderAI Sparks add-on lets it extract calendar events and tasks, including dates and descriptions.

ThunderAI is open source under GPL-3.0. Ollama processing runs fully locally and doesn't need an API key. The ChatGPT web connection requires an account but no API key; the OpenAI, Gemini and Claude API connections require keys.