AI Features
MailFellow brings AI-powered intelligence to your email workflow. Every incoming email is automatically analyzed, categorized, summarized, and, if needed, translated. Powered by your choice of OpenAI, Anthropic, or Google Gemini.
What AI Does
Every email is classified as Support, Sales, Billing, Spam, or Other. Color-coded badges appear on notifications so your team can prioritize at a glance.
Learn more →Long emails become 1-2 sentence summaries. Entire threads are distilled into a status update. Your team reads the summary; the full text is one click away.
Learn more →Non-English emails are automatically detected and translated. Replies and auto-replies are translated back to the sender's language. Supports 28+ languages.
Learn more →Emails categorized as spam are automatically blocked. The sender is added to your block list and future emails are silently discarded.
Learn more →Setting Up AI
- Go to Settings > AI
- Toggle Enable AI on
- Choose your provider
- Select a model
- Enter your API key
- Click Save
Providers and models
| Provider | Models | Get your API key |
|---|---|---|
| OpenAI | GPT-4.1 Mini (recommended), GPT-4.1 Nano, GPT-4.1, GPT-4o Mini, GPT-4o, o4-mini | platform.openai.com/api-keys |
| Anthropic | Claude Sonnet 4 (recommended), Claude Haiku 4.5, Claude Opus 4 | console.anthropic.com/settings/keys |
| Google Gemini | Gemini 2.5 Flash (recommended), Gemini 2.5 Pro, Gemini 2.0 Flash, Gemini 2.0 Flash Lite | aistudio.google.com/apikey |
Which model should I choose?
| Priority | Recommended | Why |
|---|---|---|
| Lowest cost | GPT-4.1 Nano, Claude Haiku 4.5, Gemini 2.0 Flash Lite | Fastest and cheapest, good for high-volume accounts |
| Best accuracy | GPT-4.1, Claude Sonnet 4, Gemini 2.5 Pro | Nuanced understanding for complex emails |
| Balanced | GPT-4.1 Mini, Gemini 2.5 Flash | Good accuracy at minimal cost for most teams |
Enabling Translation
- Go to Settings > AI
- Toggle Translation on
- Optionally set a default reply language
- Click Save
Translation uses the same provider and API key as categorization and summarization. See the full Translation guide for details on how incoming and outgoing translation works.
How Email Processing Works
When an email arrives, MailFellow processes it in this order:
- Summarize + Categorize (1 API call):extracts a summary and assigns a category
- Detect language + Translate (1 API call, only if translation is enabled and the email is not English):detects language, translates to English
- Forward to platform:sends the notification with summary, category badge, and translation to your chat channel
English emails skip step 2 entirely, so there is no extra cost.
Caching
All AI responses are cached for 5 minutes, keyed by the first 200 characters of the input. Benefits:
- Duplicate emails (e.g. retries) do not trigger extra API calls
- Re-processing the same email within the cache window is instant
- Cache is in-memory and resets when MailFellow restarts
Supported Languages
MailFellow recognizes and translates these languages (and any others your AI provider supports):