Browser extension for Chrome, Edge, Brave and Firefox

Write it once. Post it everywhere.

Prefill fills the post box on X, Bluesky, Threads, Mastodon and W Social with your text, your hashtags, your photo and its description. Then it stops, and you press Post. One click copies the same post for everywhere else you write.

Install free See how it works

Free for X, forever. No account. No password ever leaves your browser.

A young woman in a white jumper grins and flexes both arms in a bright living room, with her laptop on the sofa behind her.

Fills the composer on

  • X
  • Bluesky
  • Threads
  • Mastodon
  • W Social

Everywhere else

One voice, everywhere you write.

Prefill fills the composer on five platforms. For everything else there is Copy text. Your saved lines, the hashtags it remembers for you and the lettering you picked all come along, so the post that lands in Discord reads exactly like the one on X.

  • Discord
  • Slack
  • LinkedIn
  • WhatsApp
  • Newsletters
  • Forums

Copy text takes the words. Your photo and its description go to the five composers Prefill fills for you.

The difference

Five boxes. One post.

Flip the switch and see what changes.

Without Prefill With Prefill

25 jobs, one post

  1. Open five platforms, one tab each
  2. Paste the same text five times
  3. Recount the characters, because X counts every emoji twice
  4. Upload the same photo five times
  5. Write the image description five times, and trim it to each limit

How it works

Write. Choose. Press Post.

No dashboard to learn and no accounts to connect. It works inside the browser you already use.

  1. Write the post

    One composer for your text, your hashtags, a photo and its description. The hashtags you use most are waiting as you type.

  2. Pick your platforms

    Tick the ones you want. Each has its own limits, and Prefill works to every one of them.

  3. Read it, then post it

    Each platform opens in its own tab, already filled in. Press Post yourself. Changed your mind? Close the tab. Nothing was sent.

  4. A woman sitting cross-legged on a city pavement throws both arms up in delight, a laptop on her lap.

Inside Prefill

Everything in one small window.

Prefill opens from your browser toolbar. This is what is inside.

  1. Your post

    Text and hashtags, written once. The hashtags you use most appear as soon as you type #.

  2. Photo and description

    Attach a photo or video and describe it. One tick adds a note that the description is included.

  3. Saved lines

    Pick a ready line by theme, restyle text, and frame the post with emoji at either end.

  4. Your platforms

    Tick where it should go. Each counter shows the limit that platform really counts by.

  5. One button

    Prepare opens a tab for every platform, already filled in. You press Post in each one.

The Prefill window, opened from the browser toolbar: a text box for the post, buttons to copy the text and to add a photo or video, sections for hashtags, saved lines and saved posts, checkboxes for X, Bluesky, W Social, Threads and Mastodon with a character counter each, and the button that prepares the posts. Shown in Dutch. Prefill speaks eight languages.
Shown in Dutch. Prefill speaks eight languages.
A man in a blue shirt sits at his laptop among houseplants, smiling as he looks away from the screen.

Image descriptions

Describe your photo once. Every platform gets it.

People who use a screen reader rely on the description to know what is in your picture. Prefill carries it to every platform and trims it at a word boundary to that platform's limit, so nothing gets rejected.

  • X1,000
  • Threads1,000
  • Mastodon1,500
  • Bluesky2,000
  • W Social2,000

With Pro, Threads can also carry the full description as a second post in the thread, up to 10,000 characters.

Why it is safe

It never posts for you.

  • Your click, every time

    Prefill stops at the composer. The Post button is pressed by a person, on the platform's own page.

  • No passwords, anywhere

    It runs in the browser you are already signed into. No server holds your social accounts, because there is nothing to hold.

  • Nothing waiting to go out

    There is no queue and no scheduler. Close a tab and that post simply never happened.

Saved lines

The right words, already written.

381 ready-made lines for thanks, praise, questions, invitations, greetings and announcements. Drop one in at the cursor. The everyday categories speak eight languages.

🌟 Good morning!

A woman with her hair tied back laughs at her laptop at a kitchen table, a cup beside her. A woman in a red top smiles broadly at her desk in a bright office, laptop open in front of her.

For anyone who posts

One post, in every place your people are.

An older man with white hair smiles as he types on a laptop at a table by a sunny window. An older woman with short grey hair smiles from a table in a leafy garden, her laptop beside a cup. A young man sits in a window recess with a laptop on his knees, smiling as he types.

Pricing

Free for X. All five for €4.99 a month.

X keeps working forever, with no account and no payment. Pro opens every platform in one go.

Free

€0

No account, no expiry

  • Post to X
  • Your hashtag library
  • Image descriptions
  • 3 saved lines from one category
Install the extension

Pro Monthly

€4.99

per month, cancel anytime

  • Everything in Free
  • X, Bluesky, Threads, Mastodon and W Social
  • All 381 saved lines, every category
  • Two categories of your own
  • Save whole posts and send them again, pictures and all
  • Emoji sets for the start and the end of a post
  • The full image description as a second post on Threads
  • 14 day free trial
Start free trial

Two months free

Pro Yearly

€49.90

per year, about €4.16 a month

  • Everything in Pro monthly
  • Two months free compared with paying monthly
  • 14 day free trial
Start free trial

Pay with PayPal. Prices are final: no VAT is charged (Kleinunternehmer, § 19 UStG). Cancel any time from your PayPal account. A 14 day right of withdrawal applies.

Questions

Before you install.

Do I need to give you my social media passwords?

No, and there is nowhere to enter them. Prefill runs in your browser and uses the sessions you are already signed into. Your passwords never travel anywhere.

Could this get my account banned?

Automated posting breaks the rules of most platforms, which is exactly why Prefill stops short of posting. It fills the composer, and a person presses Post on the platform's own page. That is as close to posting by hand as a tool can get. No tool can promise an account will never be actioned, and we do not either.

Which browsers does it work in?

Chrome and any browser built on Chromium, including Edge, Brave and Opera. Firefox from version 128.

Can it schedule posts for later?

No. Scheduling would mean a server holding your accounts while you are away, which is exactly what Prefill is built to avoid. It prepares the post while you are there, and you send it.

What happens if I cancel?

You keep every paid platform until the end of the period you paid for. After that Prefill goes back to Free and carries on posting to X.

Can I pay by card?

Payment goes through PayPal, which handles the subscription and the recurring charge. A PayPal account is required.

What if I post somewhere you do not support?

Write it here and press Copy text. The post, your hashtags and your lettering go to the clipboard, ready to paste anywhere you write. Prefill fills the composer on five platforms, and the clipboard covers the rest. The picture and its description are not copied with the text.

Your post is ready. The click is yours.

Free for X today. All five platforms whenever you want them.

Install free