September 21, 2026

Connecting X to PostBox

X is the one platform that asks you to bring an app of your own.

Or do it yourself, in seven steps

1. 1

   Join the X Developer Program

   Sign in with the X account you want to post from, tick the three boxes, and paste the description below into the use-case box.

   I use the X API to publish to my own X account from PostBox, a Mac app I use to write and schedule posts. My use is limited to four things: - Creating posts on my own account — text, images and video (POST /2/tweets and the /2/media/upload endpoints). - Deleting posts I made through the app (DELETE /2/tweets/:id). - Reading my own profile at sign-in, so the app can show me which account is connected (GET /2/users/me). - Refreshing my own access token so I do not have to sign in again (offline.access). I do not collect, store, analyse, display or redistribute any other X user's data. I do not read timelines, search results, or follower data. Nothing received from the X API is sent to any server: the app runs entirely on my Mac and keeps the access token in the macOS Keychain. Nothing is resold or shared with anyone. The read scopes (tweet.read, users.read) are requested only because X requires them alongside tweet.write. They are not used to retrieve anyone else's content. Copy the description

   Read it before you paste it, because it goes on the form under your name.

   

2. 2

   Open the X developer console

   Enrolment drops you at console.x.com, so check the avatar in the corner is the account you meant.

   

3. 3

   Open the app X already made you

   Open Apps in the left nav and open the app already sitting there, because enrolment made one for you and its name is what X shows as the post’s source.

   

4. 4

   Set it up as a Native App

   In the app’s Keys & Tokens tab press Set up under User authentication settings, then choose Read and write, pick Native App, and paste postbox://x-callback as the Callback URI exactly as written.

   

5. 5

   Copy the Client ID

   Saving pops a dialog with two values in it — copy the Client ID, never the Client Secret underneath.

   

6. 6

   Paste it into PostBox and sign in

   Paste it into the notch and press Connect X, then tick “I trust this app” on X’s page, which is X describing the app you just made back to you.

   

7. 7

   Buy credits before your first post

   Open Billing → Credits, add a payment method, buy credits and turn on Auto Recharge, because a connection with an empty balance looks exactly like a working one until the first post fails.

   

Open the X developer console →

If the sign-in does not finish

X says something went wrong before you can approve

Check you copied the Client ID and not the App ID — the short all-digits number beside it — and that the Callback URI reads postbox://x-callback exactly, with no trailing slash, because X matches it character for character.

You approved on X, and PostBox never noticed

If you keep more than one copy of PostBox, macOS can hand the finished sign-in to the wrong one, so trash the spare and sign in again.

“That sign-in expired” or “Use the newer tab”

Only the most recent sign-in counts, so press Connect X again and finish that tab.

You have two X accounts and only one gets the post

Open Settings → Connections and read the two X rows: different handles means the quiet account has run out of credits, and the same handle twice means that sign-in reused your browser's session, so disconnect it, switch accounts on x.com and connect it again.

It connected, then a post failed

Check your credit balance, and if a picture failed where text alone would have worked, the app is set to Read only — set it to Read and write and sign in again.

Posting to more than one X account

PostBox is not limited to one X account, but a second one is a second everything on X's side — its own enrolment, its own app, its own Client ID, and its own credits.

That last one is what catches people, because an account you connected but never bought credits for shows as Connected and silently posts nothing.

Switch accounts on x.com before you press Connect X the second time, because X's approval page has no account picker and will quietly grant for whoever your browser is already signed in as.

Why your own app, and what PostBox keeps

Your own app spends your own credits, so nothing anyone else does can take your posting away. It is also why X costs you nothing in PostBox: there is no allowance to meter and no plan to sell you. Every other platform still connects with one press.

The Client ID is not a secret — it travels in the address bar when you sign in, and it only names your app. PostBox never asks for your Client Secret and never sends one. What can actually post is created by the sign-in, never typed, and kept in your Mac's Keychain. PostBox has no account and no database, so there is no copy of it on a server of ours to lose. Revoke it any time from your X account's connected apps, or disconnect X in PostBox.

Stuck on something this page does not answer, write to [email protected]. Also here: Privacy Policy.