Schedule validator

Paste a schedule and it finds the four errors a calendar view hides: duplicates, dead hours, same-network collisions and dates that do not exist.

What it checks

  • Duplicates — the same network at the same minute twice. Usually a CSV imported twice, and the reason is invisible in a calendar because both blocks land on the same day.
  • Dead hours — anything between 01:00 and 05:00. Almost never deliberate; usually a bulk operation that spread posts across the clock rather than across the waking day.
  • Rate-limit collisions — two posts to the same network inside five minutes. Some platforms return a clean 429. The dangerous ones accept both and drop one.
  • Impossible dates — 2026-08-32, or 25:00. These fail at publish time, hours after you queued them.

The two it cannot check

Two of the five common scheduling failures are properties of your tool, not of a list of timestamps:

Timezone drift. If your scheduler stores a local time plus a timezone rather than an absolute instant, every future post shifts by an hour across a daylight-saving boundary. Ask what it stores; if the API round-trips ISO-8601 with an offset, you are fine.

The reconnect gap. If a token expires mid-queue, everything scheduled during the gap fails. The defence is a warning before expiry, not an error after it.

Both are covered in five scheduling mistakes that double-post.

Questions

Is my schedule uploaded?

No. Parsing and checking happen in your browser. Nothing leaves the page, which matters because a posting schedule is a reasonable thing to consider confidential.

Why flag 01:00–05:00 specifically?

It is the window where engagement collapses for essentially every consumer audience. If you post deliberately at 3am for a different timezone, ignore the warning — but it is worth being deliberate about.

Why five minutes for the collision check?

It is the interval below which per-account rate limiting starts to bite on most networks. Two posts ten minutes apart are fine; four inside a minute are not.

What format does it expect?

One post per line, as YYYY-MM-DD HH:MM followed by a network name. Most schedulers can export something close to this, and reformatting a column in a spreadsheet is usually a minute of work.