Answer your email with AI, without losing your voice

What AI does well in an inbox

• Summarize a long thread: who is waiting for what, by when, and what is still to be decided.
• Prepare a draft from three words from you, in the tone you ask for.
• Rework your text: shorter, firmer, more diplomatic, with no mistakes.
• Sort: what needs a reply, what is to read, what can wait.
• Follow up: spot the email that got no answer and suggest the follow-up.
• Translate a message you received, or the one you are writing.

What it does not know: today’s prices, your inventory, what you promised on the phone yesterday. A draft can be polite and wrong. That is why the tools in this guide prepare a draft and leave the sending to you.

Keeping your voice: the method

An email written by an AI is easy to spot when it was given nothing to work with: hollow phrases, put-on enthusiasm, three paragraphs to say yes. The fix comes down to five moves.

1. Show your own emails. Paste two or three messages you have written and ask: “Reply in this tone.” An example says more than a description.
2. Give the substance, not the form. Say what your answer is, in rough notes: “yes for Thursday, not before 2 pm, the purchase order is missing.” The assistant shapes the message; it does not decide for you.
3. Set your rules once. Length, level of formality, sign-off, words you never use. Store them in a project or in your assistant’s custom instructions, so you do not have to repeat them.
4. Forbid additions. “Do not add any promise, discount, or deadline I did not give.” A price or a deadline written by the AI commits you as if you had written it yourself.
5. Review, and rewrite one sentence. Check the name, the date, and the amount against the original message. Rewrite the first line yourself: it is the one that carries your voice.

An example

Before: “Reply to this email.”

After: “Reply to this email from a customer asking to postpone a delivery. I am declining the postponement, but I am offering a partial delivery on Tuesday. Friendly and direct tone, formal, 100 words at most, like the two emails I am pasting as examples. Do not add any commitment I did not give.”

The full method is in our guide: how to write a good prompt.

Which tool, depending on your email

Plans and prices checked on October 3, 2026 on the vendors’ pages, as shown from France.

At work, look first at Gemini or Copilot: if your company has Google Workspace or Microsoft 365, the assistant is often already there, with no other subscription. Fyxer suits people who are buried in messages and want to keep their email as it is. Spark brings several addresses together in one app. Shortwave works only with Gmail, and Superhuman is aimed at people who drive everything from the keyboard.

Copying and pasting into ChatGPT, Claude, or Mistral Vibe is still the simplest way to start: no access to your inbox, and you choose what the assistant sees.

Before you connect a tool to your inbox

A tool that sorts your mail or prepares your replies reads your whole inbox: that is the condition for it to work. Your inbox holds messages from your customers and your colleagues, and sometimes sensitive attachments.

• Get your IT team’s approval before you connect a work address to an outside app. Some companies forbid it.
• Look at where the data goes. Fyxer says it stores it in the European Union; Shortwave processes it in the United States, and Superhuman is an American vendor.
• Keep approval before sending. If an assistant offers to act without asking, reserve that freedom for reading. To send, reply, or delete, approve every time.
• Be wary of summaries. An assistant can get a figure, a date, or a name wrong when it summarizes your emails. For what matters, open the original message.

For what should never go into an assistant, see what not to share with AI at work.

What Nova brings

Nova is subscription software. You will find demos to recreate on your own messages, with the prompt ready: an inbox sorted with the replies already drafted, an email dictated by voice, the customer emails left unanswered every Monday. Each tool page specifies the plan required and what the tool does with your data. Try the interactive demo.

Frequently asked questions

Can AI answer my emails on its own?

It can prepare the reply, not take responsibility for it. The tools in this guide write a draft that you review and send; Fyxer, for example, never sends anything. Keep that approval step: a draft can contain a price, a date, or a promise you did not give.

How do you keep an email from sounding like it was written by AI?

Give two or three of your emails as examples, state the substance in a few words, limit the length, and forbid additions. Then rewrite the first sentence yourself. A short, precise message in your tone reads like an email you typed.

Is Gemini in Gmail free?

No. The “Ask Gemini” button in Gmail requires Google AI Plus, at €4.99 per month in France, or a Google Workspace plan. However, the free Gemini app can search your Gmail messages if you allow it, through connected apps.

What if my company uses Outlook?

Copilot summarizes a thread and prepares a reply in Outlook. At work, this is included with Copilot Chat in eligible Microsoft 365 subscriptions: check what your company has turned on before you pay for anything.

Is it risky to connect a work inbox to an AI tool?

It calls for a company decision, not a personal initiative. The tool reads all your messages, including those from your customers and your colleagues. Get your IT team’s approval and, for personal data, ask the data protection officer.

Sources

• Google AI plans (France, in French), Google
• Microsoft 365 Copilot pricing (France, in French), Microsoft
• Fyxer pricing, Fyxer
• Fyxer security, Fyxer
• Spark pricing, Spark Mail
• Shortwave pricing, Shortwave
• Superhuman Mail plans, Superhuman

Go further

• Gemini, in Gmail, Docs, and Calendar
• Microsoft Copilot, in Outlook and Teams
• Fyxer: draft replies in your style
• Spark Mail: all your addresses in one place
• Shortwave, for Gmail
• Superhuman Mail
• ChatGPT: the full tool page
• Claude: the full tool page
• Mistral Vibe, the French assistant
• AI meeting notes
• AI training for executive assistants
• AI training for sales representatives
• AI training for customer service representatives
• AI training: all jobs