llms.txt
# PostBox
> PostBox turns the MacBook notch into a drag and drop poster. Drag a file in, write the caption once, and it goes to YouTube, Threads, Instagram, Bluesky, Dribbble, LinkedIn, X and TikTok at once. Shaped for each one and posted from your Mac.
PostBox is a native macOS app for anyone who wants a finished file
seen without turning posting into a second job.
The problem it solves is the half-hour after the work is finished:
signing into five platforms, re-exporting the same file at whatever
ratio each feed crops to, rewriting one caption into three boxes with
three character limits, and typing the same eight tags again — usually
at the end of a day already spent making the thing. Most people give up
somewhere around the third platform, so good work ends up posted in one
place or in none.
PostBox makes that one action. It puts a drag-and-drop tray in the
MacBook notch: drag a file toward the top of the screen — a photo, a
screen recording, a slide — and the tray opens to meet it.
You write one caption, pick the platforms, and one click fans the post
out to all of them, shaped for each destination rather than cropped
by it. There is no window to find and no browser tab to open, and the
posts go out from your own Mac on accounts you connected yourself.
## Who it is for
- Anyone who posts from a Mac to more than one platform.
- People who keep a social presence and are tired of doing each post twice.
- Teams of one who would rather make the next thing than open eleven tabs.
It is not a content-marketing tool. There is no scheduler, no analytics
dashboard, no engagement score, and no AI writing the caption for you —
the caption field is deliberately left alone, because that sentence is
yours.
## What it replaces
- Opening one browser tab per platform, and signing in again on each.
- Re-exporting a design at 4:3 for one feed and 4:5 for another.
- Rewriting one caption into a title box, a description box and a tag field.
- Deciding a piece is not worth the admin and never posting it at all.
## Facts
- Platform: macOS only. Requires macOS 15 or later.
- Distribution: direct download, signed and notarized. Not on the Mac App Store.
- Updates: automatic, in-app.
- Website: https://postbox.sh
## Posting today
These post end to end, images included, with a link back to each post:
- YouTube
- Threads
- Instagram
- Bluesky
- Dribbble
- LinkedIn
- X
- TikTok
## Pricing
PostBox is free. There is no paid plan, no subscription, no account and
no limit — not on posts, not on platforms, not on how many accounts you
connect to each one, and not on how many Macs you install it on.
Download the app to get started.
## Privacy
- There is no PostBox account. No sign-up, no email address, no
sign-in code, no device identifier and no database. Nothing that
identifies you is held.
- What PostBox stores is one revocable credential per connected
account, in your Mac's Keychain and nowhere else. Disconnecting a
platform deletes it. A note published on 19 September 2026 said an
encrypted copy was also kept on our servers; that was reversed the
same week and no server copy exists.
- **Signing in takes one of three shapes, and they differ in what
touches our server.** (1) X, YouTube and TikTok: you sign in on the
platform's own page and the code-for-token exchange happens on your
Mac using PKCE, so nothing passes through us. (2) Threads, Instagram,
LinkedIn and Dribbble: you still sign in on the platform's own page,
but those four publish no PKCE flow and will only issue a token to a
holder of an app secret — which cannot ship inside a download — so
the token is relayed through our server once and handed straight to
your Mac. It is never written down. (3) Bluesky and X's API keys: you
paste a credential you generated yourself on that platform. Your
account password is never typed into PostBox and never sent to
us in any of the three.
- No analytics on either surface. The website sets no cookies and makes
no third-party request; the app sends no telemetry. The one exception
is the home page's demo: pressing "Play with sound" loads YouTube's
privacy-enhanced player, and nothing of Google's is requested before
that press.
- X is API-only, and bring-your-own-keys. You paste the API Key, API Key
Secret, Access Token and Access Token Secret from your own X developer
account, so X posts spend your own project rather than a shared one.
PostBox never signs in to or drives x.com and never sends those
credentials to our servers.
- Drafts and attached files stay on your Mac, in ~/Documents/PostBox/.
- Posting happens from your Mac, so for almost every platform your
captions, images and videos do not pass through us. We keep no copy of
anything you post.
- The exception is images and videos posted to **Threads and
Instagram**, and it is not optional: Meta's APIs will not accept a
file, only a web address they fetch themselves. For those two
platforms the file is uploaded to a private Cloudflare R2 bucket we
run, handed to Meta as a single-use expiring link, and deleted as soon
as the post is published — with the bucket removing anything left
within 24 hours regardless. Full detail: https://postbox.sh/privacy
## Common questions
- **What does PostBox do?** Drop finished work into your MacBook notch, write one caption, choose the destinations, and post.
- **What does it cost?** Free.
- **What do I need for X?** Your own X API tokens. Add them in PostBox before posting to X.
- **Does it change my original file?** No. Crops, compositions, and delivery versions are separate copies.
- **Can I schedule posts?** Yes. Scheduling is included.
- **Can I use more than one account on the same platform?** Yes. Add as many as you need.
- **What happens if a post fails?** The draft stays put. PostBox shows which destination failed so you can retry it.
## Pages
- [PostBox: From finished to posted](https://postbox.sh/): PostBox turns the MacBook notch into a drag and drop poster. Drag a file in, write the caption once, and it goes to YouTube, Threads, Instagram, Bluesky, Dribbble, LinkedIn, X and TikTok at once. Shaped for each one and posted from your Mac.
- [Privacy Policy](https://postbox.sh/privacy): The PostBox privacy policy. Posting happens on your Mac, your account passwords are never stored, and your drafts stay in your own Documents folder. The one exception — images posted to Threads and Instagram — is named in full.
- [Terms of Service](https://postbox.sh/terms): The terms of service for PostBox — what you can expect from the app, what we ask of you, and how the licence works. PostBox is free: there is no plan and no billing.
- [Copyright and Takedowns](https://postbox.sh/dmca): How to report copyright infringement to PostBox: our registered DMCA designated agent, what a valid notice must contain, how to send a counter-notice, and our repeat-infringer policy.
- [Connecting X to PostBox: your Client ID and billing](https://postbox.sh/x-keys): How to join the X Developer Program, make an X app of your own, and copy the one Client ID PostBox asks for. Seven steps with the use-case description to paste, or a prompt you can hand to Grok or Claude, plus the two values that look right and are not and what X charges per post.
## Contact
- Email: hello@postbox.sh
- Bugs, feedback and feature requests: hello@postbox.sh
