For people who post on X

Learn what works on your X account. And what to stop posting.

Crux is in early access. It reads your own X post history, from an archive upload or an X import, and finds the hooks, formats, topics and posting times that actually work for your account.

Crux asks X for read-only access. It cannot post, like, follow or read your messages.

In development: daily scores for posting openings in your niche, and drafts checked against your own rules. Not available yet.

Today · 5 openingsSample data

X API pay-per-use is breaking indie tools

Three tools in your feed changed pricing in the last 18 hours and none explained the maths.

Momentum94 — accelerating fast

Audience96 — almost everyone you reach cares

Fit91 — sounds like you already

CrowdingLow — room to be first

Postgres 19 beta benchmarks

Loud topic, wrong room. You have never posted about databases.

Momentum89 — loud, but not in your room

Audience34 — only a third of your followers care

Fit21 — nothing in your history backs this

CrowdingHigh — database accounts own it

Crux would not lead with this.

A preview of the Today feed, in development. Every score reads as a sentence, never a bare number.

What the film shows: planned features, with sample data.

It starts from the scored opening “X API pay-per-use is breaking indie tools” (Momentum 94, Audience 96, Fit 91, Crowding low), with a data-driven angle suggested.
Write this opens the composer, and a draft that does the maths nobody explained streams in, word by word.
The draft is checked against your own rules: opens on a number, no hype phrases, and the window is still open, ahead of the crowd.
Copy confirms the draft is copied, then Open on X hands it over: you publish the post on X yourself. An hour later Crux measures your post: its reach is 2.4 times your median, with 41 replies, 63 reposts and 208 bookmarks. Then the film loops.

A preview film with sample data. Opening scores and drafting are in development, and Crux will never post for you: once they ship, you copy a draft and post it on X yourself.

The problem

Most tools optimise for volume. That is why your feed looks like everyone else’s.

Generators will happily write you five posts about whatever is trending. They do not know that a third of your followers have never engaged with that subject, that forty accounts already posted the same chart this morning, or that you have no history to back the take.

Crux starts from the opposite end: what has already worked, and what has not, on your own account. Often its most useful answer is that a topic or format you keep coming back to does worse than usual for you.

How it works

Three steps, and none of them post for you.

Bring your post history

Upload tweets.js from your X archive, or import your posts through X with read-only access. Crux needs your writing and its numbers, not your photos or messages.

Each post is measured against your own baseline

Reach grows with your follower count, so Crux compares every post with the twenty or so posts nearest it in time, not with your all-time average. An early post and last week’s post are judged on the same scale.

Only patterns that hold up are reported

Crux groups your posts by hook, format, topic and posting time and tests each group. A small group that happens to look good is left out instead of being shown as a finding.

In development

A copilot that says “not this one”.

Opening scores are not available yet. When they ship, Crux will dim the openings it scores badly instead of hiding them, and show the numbers behind the verdict. You will always be able to overrule it. But you will know what you are overruling.

A tool that only ever says yes is not giving you judgement. It is giving you volume.

Today · 5 openingsSample data

Postgres 19 beta benchmarks

Loud topic, wrong room. You have never posted about databases.

Momentum89 — loud, but not in your room

Audience34 — only a third of your followers care

Fit21 — nothing in your history backs this

CrowdingHigh — database accounts own it

Crux would not lead with this.

A sample opening, scored and set aside. A preview: opening scores are not available yet.

Where we stand

Three things Crux will not do.

Post without you

Crux connects with read-only X permissions. It cannot publish, reply or schedule anything.

Farm engagement

No reply-guy automation, no follow-unfollow, no hooks engineered to bait a quote tweet. Those work until they do not.

Sell or train on your data

Your posts are used to analyse your account and nobody else’s. Crux never reads your messages.

FAQ

Questions

What is Crux (Cruxpost)?

Crux, at cruxpost.com, is an early-access tool for people who post on X (formerly Twitter). It reads your own post history and shows which hooks, formats, topics and posting times do better or worse than usual for your account. Daily opening scores and drafting are in development and not available yet. Crux is not affiliated with X Corp.

What does Crux need from my X account?

Read-only access through the X permissions tweet.read, users.read and offline.access. They let Crux read your posts and profile and stay connected without asking you to sign in again. Crux does not ask for permission to post, like, follow or read direct messages. You can also upload tweets.js from your X archive instead of importing through X.

How does Crux decide a pattern is real?

Each post is compared with the posts published around the same time on your account, so follower growth does not distort the result. Posts are then grouped by hook, format, topic and posting time, and a group is reported only when it passes a significance check. A handful of lucky posts is not presented as a rule.

Which parts of my X archive does Crux use?

tweets.js (including its -part files), note-tweet.js and account.js. They hold your posts, long-form notes and basic account details. Photos, videos and direct messages are not needed, so the recommended upload leaves them out.

Does Crux post for me?

No. Crux connects with read-only X permissions, so it cannot publish, reply, like or follow on your behalf. Anything you post, you post yourself on X.

How much does Crux cost?

Crux is in invite-only early access and nobody is charged. Paid plans are planned but not on sale yet; the pricing page shows what they are expected to include.

Stop guessing what works for your account.

Crux is in early access. Ask for an invite and bring your X archive.