ChainMail
The privacy problem with AI email tools
AI-powered email writing has become mainstream. Gmail has Gemini. Outlook has Copilot. Dozens of startups offer Chrome extensions that draft, summarize, and reply to emails. They all have one thing in common: your email data goes through their servers.
When you use an AI email extension or built-in AI feature, the service typically:
- Reads the email thread you're replying to
- Sends that content to their AI backend for processing
- May store or log the content for model improvement
- Returns a suggested draft
For personal email, this may be acceptable. But for business email — especially in industries with confidentiality requirements (legal, finance, healthcare, consulting) — sending email content to a third-party AI service creates a data handling risk you may not be comfortable with.
ChainMail never sees your email content. AI requests go directly from your computer to the provider you choose, using your own API key.
How ChainMail's BYOK approach works
BYOK = Bring Your Own Key. Instead of routing your data through our servers, ChainMail lets you connect directly to the AI provider of your choice using your own API key.
Step 1: Choose your provider
ChainMail supports six AI providers:
- OpenAI — GPT-4o, GPT-4o Mini, GPT-4.1, and more
- Anthropic — Claude Sonnet, Claude Haiku
- Google — Gemini 2.5 Pro, Gemini 2.5 Flash
- Grok (xAI) — Grok 3, Grok 3 Mini
- OpenRouter — access to 100+ models through a single API
- Ollama — run AI models locally on your own hardware (completely offline)
Step 2: Enter your API key
Go to Settings > AI, select your provider, and paste your API key. The key is encrypted and stored locally on your machine. ChainMail never transmits your API key to our servers.
Step 3: Draft with AI
In the compose window, click the AI button. Type an instruction like "Reply professionally, decline the meeting but suggest next week" or "Write a follow-up checking on the proposal status." ChainMail sends the instruction and email context directly to your chosen provider and displays the generated draft.
You can preview the draft before inserting it, regenerate with a different instruction, or edit it after insertion.
What makes this different
| Aspect | Typical AI Email Tools | ChainMail (BYOK) |
|---|---|---|
| Data flow | Your email → their servers → AI provider | Your email → AI provider (direct) |
| Who handles your data | The tool company + AI provider | Only the AI provider you choose |
| API key ownership | Their key (shared infrastructure) | Your key (your account, your usage limits) |
| Cost model | Monthly subscription ($10-30/mo) | Pay-per-use via your API key (often pennies) |
| Provider choice | Usually one provider | 6 providers + local Ollama |
| Offline option | ✕ | ✓ Ollama (local) |
| Data logging | Varies (often used for training) | Your provider's policy (you control) |
The Ollama option: fully offline AI
For users who want AI drafting with zero data leaving their machine, ChainMail supports Ollama — a tool that runs AI models locally on your computer.
With Ollama, the AI model runs on your CPU or GPU. No API key needed. No internet connection needed. Your email content never leaves your machine, period.
This is ideal for:
- Organizations with strict data residency requirements
- Users handling confidential or privileged communications
- Anyone who wants AI assistance without any data exposure
Context-aware drafting
ChainMail doesn't just generate generic text. When you're replying to an email, the AI sees:
- The email you're replying to (truncated to avoid excessive token usage)
- Your name and signature
- Your instruction for the draft
This means the AI produces replies that reference the original message, match your tone, and include your signature automatically.
Cost comparison
Most AI email services charge $10–30 per month. With ChainMail's BYOK approach, you pay the AI provider directly based on actual usage. For typical email drafting:
- OpenAI GPT-4o Mini: ~$0.001 per draft (less than a tenth of a cent)
- Anthropic Claude Haiku: ~$0.001 per draft
- Ollama (local): $0 (runs on your hardware)
Even heavy email users drafting 50 AI emails per day would spend under $2/month with a cloud provider. Most users spend cents.
Frequently Asked Questions
Does ChainMail see my emails or AI drafts?
No. ChainMail sends the AI request directly from your computer to your chosen provider. The request never passes through ChainMail's servers. We have no ability to read your email content or AI-generated drafts.
Where is my API key stored?
Your API key is encrypted and stored locally on your computer using your operating system's secure storage. It is never transmitted to ChainMail's servers.
Can I use AI drafting with email templates?
Yes. You can insert a template first and then use AI to personalize or extend it. Or you can use AI to generate a draft from scratch. The two features work together.
What happens if I don't have an API key?
AI drafting is entirely optional. ChainMail works as a full-featured email client without it. If you later decide to try AI drafting, you can sign up for any supported provider and add your key in Settings.
Can I switch AI providers?
Yes. You can change providers at any time in Settings > AI. Select a new provider, enter your key, and you're set. There's no lock-in.
Is the AI drafting feature included in the base price?
Yes. AI drafting is included in ChainMail at no additional cost. You only pay your AI provider for API usage, which is typically very low (pennies per draft).