Reply to anything

Paste any message — email, WhatsApp, a DM — say what you want to get across, and get a reply written in your own voice.

Replyku is a small tool for one job: you paste a message somebody sent you, and it writes the reply. Not a chat assistant, not a general writing app — a reply, in the register the original was written in, in a voice you can teach it.

How it works

  1. Paste what you received

    The whole message, not a summary. The greeting, the sign-off and the punctuation are what tell the model whether this is a contract negotiation or your cousin asking about the weekend, and cutting them out is the single most common reason a draft comes back at the wrong pitch.

  2. Say what you want to get across

    One line is enough — "say yes but push the date to November", "decline politely, I don't want to work with them again", "ask for the invoice without sounding annoyed". This field is optional, but it is the difference between a reply that is merely polite and one that does what you needed it to do.

  3. Set the shape, then edit what comes back

    Format decides whether you get an email or a chat message, tone sets the distance, length caps it. What comes out is a draft: read it, cut the sentence that isn't true about your situation, and send it. Nothing is stored, so nothing is waiting for you next time.

Written guides

For the replies worth thinking about rather than generating: hand-written guides on what to say, in what order, with full worked examples.

Read the guides

What people use it for

The messages that get put off are rarely the complicated ones. They are the ones with something socially awkward in them — a refusal, a delay, a disagreement, or bad news.

  • Declining an invitation, a project, or a request from someone you will see again.
  • Replying to a client who is angry, or to one who is wrong.
  • Answering a message you left sitting for three weeks.
  • Job applications, interview follow-ups, offers, and rejections in both directions.
  • Chasing an invoice without escalating a working relationship.
  • Writing in a second language to someone who will read it in their first.

Sounding like you, not like a template

Every AI writing tool has a default voice, and everyone can recognise it by now — the balanced sentences, the enthusiasm, the closing line that offers to help further. A reply that reads that way is worse than a clumsy one you wrote yourself, because the person reading it knows you didn't.

The writing-samples field is the fix. Paste two or three messages you have actually sent — real ones, including the ones where you were blunt or used no punctuation — and the drafts pick up your sentence length, your greetings, and the things you never say. It does more for the output than any of the tone buttons.

Those samples are your own writing, so they stay in your browser's local storage. They are sent with a request only when you ask for a draft, and there is no account they could be attached to.

What happens to the message you paste

It goes to the server, and from there to the model that writes the reply. It is not written to a database or a log file, there is no history, and no account exists to hold one. When the response finishes, the text is gone.

That is a deliberate constraint rather than a feature: people paste private mail into this box, and the only honest way to handle it is to keep nothing.

Privacy

What it won't do well

It doesn't know anything about your situation beyond what you paste. Facts it wasn't given — dates, amounts, names, what you actually agreed last month — will be missing or invented, so read for those before sending.

It won't refuse on your behalf. If a reply needs to end a relationship, dispute a charge, or say something with legal weight, the draft is a starting point and the judgement stays yours.

It only replies. Paste something that isn't a message and it will say so rather than write an essay.

Questions

Is it free?
Yes, with a limit on how many drafts one visitor can generate in a session so a single user can't monopolise the machine. The site is funded by the ads on it.
Do I need an account?
No. There is no sign-up, and nothing to log into. Your writing samples and theme preference live in your browser, not on the server.
Which languages does it work in?
The interface is in English and Indonesian. Drafts follow the language of the message you paste, so replying in another language works as long as the original is in it.
Can I use the drafts at work?
Yes. What comes out is yours to send, edit, or throw away. Check it first — the responsibility for what you send is not something a tool can take on.
Will the person I'm replying to know it was AI-written?
If you send the first draft unedited, quite possibly. If you fill in the writing-samples field and cut the sentences that aren't yours, much less likely. Treat it as a first pass, not a finished message.
Is my message used to train a model?
Not by us — we keep nothing. The text is processed by the model provider named in the privacy page, and their handling is covered by their own policy, which is worth reading if this matters to you.