FlyMail vs Grammarly for Email

The short version before the details

These two tools overlap less than the search results suggest. People type "grammarly ai email writer" expecting a drafting tool, and Grammarly does have generative features, but its center of gravity is editing. You write something, it marks problems and suggests fixes.

FlyMail starts from the other end. You describe the email in a sentence, and it returns a greeting, body and sign-off. FlyMail is ours (EmailAI.me is run by ATN Marketing SRL, the developer of the app), so weigh our opinion accordingly. We have tried to stick to what each product is documented to do.

What Grammarly does well with email

Grammarly's advantage is reach. It has a browser extension, desktop apps and a phone keyboard, so the same checks follow you into Gmail in a browser, a Slack box or a text field in some other app. You never switch tools; the suggestions appear where you are already typing.

It is strongest as an editor. If you have written the email yourself and want typos, grammar slips and unclear sentences caught, that is its home ground. It also has generative rewrites, and there is a free tier alongside paid plans.

Where it is weaker, going by its own positioning, is the blank page. Staring at an empty reply box with no idea how to start is a drafting problem, and an editor has little to edit yet.

What FlyMail does well with email

FlyMail is an app for iPhone, iPad and Android with four modes on one screen: Write, Reply, Grammar and Improve. Write takes a request such as "tell a client the delivery is late" and returns a complete email. Reply takes the message you received, which you paste in, plus an optional note on how to answer, and an intent chip like Interested or Considering.

The controls are email-specific. You pick Email or Messenger style, Short, Medium or Long, and one of 30+ tones (Formal, Friendly, Persuasive and so on) in more than 20 languages. There is also a Chatbots tab with 30 specialized assistants, including Cold Outreach, Follow-Up Writer and Customer Support Replies, where you can go back and forth with "make it shorter" or "more formal".

The limits are real. FlyMail does not read your inbox and is not an email client. You paste or photograph the text, then copy, share or send the result through Gmail, Outlook or Apple Mail. There is no web version and no browser extension. A vague request gets a generic draft, and it can invent a date or a name, so read before sending.

Side by side

The same email, handled both ways

Say a customer asks when their order ships and you are late. With an editor, you type the reply first, then clean it up. A rough version might be:

hi sam, sorry the order is late, its been delayed at warehouse, should ship thursday i think

Grammarly would fix the capitalization, the apostrophe and the comma problems, and might suggest firmer wording than "i think". You still supply every fact and decide the structure.

With FlyMail you would type something like "Tell Sam his order is delayed at the warehouse and will ship Thursday, apologize, offer to answer questions" and get a finished draft:

Hi Sam,

I'm sorry your order is running late. It was held up at our warehouse, and it is now scheduled to ship on Thursday.

If you have any questions before then, reply here and I'll help right away.

Best regards,

[Your name]

Note that the Thursday date came from your request. If you leave it out, the app may guess one, and that is the mistake to watch for.

Grammar checking is where they meet

Both tools can check email grammar, which is why people compare them. FlyMail has a Grammar mode that corrects spelling, grammar and punctuation in a pasted draft, and an Improve mode that rewrites for tone and tightness. It works on a block of text you paste, not live as you type.

Grammarly does the live version, underlining as you go in whatever app you use. If most of your email is typed on a laptop in a browser, that always-on checking is hard to beat with a paste-in app. If most of your email is on a phone and you want a whole message produced for you, the balance shifts.

Other options you may be weighing

If you are comparing against a general chatbot, ChatGPT for emails works when you write a good prompt each time, but it has no email modes or tone presets. Gemini in Gmail and Copilot in Outlook draft inside their own mail apps only. For a wider list, see our guide to AI email writer apps for iPhone and Android.

Using both without overlap

Plenty of people will not need to choose. A workable split is to draft or reply in FlyMail on your phone, copy the result into your mail app, and let Grammarly (keyboard or extension) catch anything left when you edit by hand.

If you can only pick one, ask where your pain is. Blank-page drafting and replies on the go point to FlyMail. Typos and sloppy sentences in email you already write point to Grammarly. When a draft exists but sounds off and you want to rewrite an email in a different tone, either tool can do it, and FlyMail's Improve tab is built for exactly that.