An Instagram post scheduler that catches what breaks
Feed posts, carousels, Reels and Stories from one calendar — and a check before each one that knows what Instagram actually rejects.
Every Instagram scheduling tool does the same thing: you write a caption, attach an image, pick a time, and find out whether Instagram accepted it when you look at your phone hours later. The scheduling is the easy part. Knowing what Instagram will refuse is the part that costs you a post.
Instagram is stricter than the other networks, and the strictness lives in the publishing API that every scheduler goes through — including the ones built by Meta. That API refuses feed images outside a narrow range of proportions, refuses posts with no image at all, and in a carousel the first item decides the shape of every item after it. Separately, and less dramatically, hashtags went from thirty to five in December 2025.
Everything below is what Ignix checks before a post is queued, taken from the same rules the composer enforces. It is also, mostly, free to know — so read it even if you never sign up.
What you can schedule, and what Instagram decides for you
One thing worth knowing first: on Instagram you barely choose the format. Feed post, carousel and Reel are worked out from what you attach. The one you do pick is Story, a switch in the composer — and Ignix shows you the result before you queue it.
Feed post
One photo. Caption up to 2,200 characters. Instagram will not accept a post with no media at all, so a text-only update is not an option here the way it is on X or LinkedIn.
Carousel
Two to ten items, and photos and videos can be mixed in the same one. Attach more than one image and it becomes a carousel automatically — there is no format to pick.
Reel
To schedule Instagram Reels you attach a single video and pick a time — Instagram decides the rest. One video on its own always publishes as a Reel; attach a second file and the whole thing becomes a carousel instead. There is also a switch to show the Reel in your feed as well.
Story
You schedule Instagram Stories with a switch in the composer — the one format you mark yourself. It is also the only one where a 9:16 vertical image is expected rather than a problem.
The five things that make an Instagram post fail
These are the ones that come up again and again. Each is checked in the composer before the post is queued, with the specific number that applies.
The image is a shape the API will not take
Instagram’s publishing API accepts feed images between 4:5 (tall) and 1.91:1 (wide), and it is one of the reasons a scheduled post most often fails to appear. The case worth knowing is 3:4 — 1080×1440, what most phone cameras default to. Instagram itself has accepted 3:4 in the app since 2025, but it sits below 4:5, so the API refuses it and no scheduler can publish it as it is. Ours included.
In Ignix: The composer measures every image you attach and tells you the ratio it found against the range Instagram accepts, so a 3:4 photo is caught while you are still writing. There is a crop tool on the same screen with 4:5, 1:1 and 1.91:1 presets, so you fix it without leaving the page — or send it as a Story, where 9:16 is what it wants.
The carousel cropped everything after the first slide
In an Instagram carousel the first item sets the ratio for all of them. Put a square photo first and a tall one second and the tall one is cropped to square, silently, after it has published.
In Ignix: Ignix compares the items before you queue and warns as soon as the shapes are mixed, because the first one is about to reshape the rest. Crop them to a common ratio — the crop tool is right there — and the warning goes.
More hashtags than Instagram now counts
Instagram cut the limit from thirty to five in December 2025, rolled out gradually, and the five cover the caption and the first comment together — parking the extras in a comment no longer buys you slots. Instagram has not said what happens to the ones beyond five, so treat this as a limit to respect rather than a post that fails.
In Ignix: The caption gets counted before publishing, and if there are more than five you are offered a one-click trim that keeps the first five and turns the rest back into plain words. Hashtags you put in the first comment are not counted yet — that is on us to fix.
The file format is not one Instagram takes
Meta’s own documentation says JPEG is the only image format Instagram supports. PNG often goes through anyway; WebP and GIF do not, and Facebook takes both — which catches people out when the same post goes to the two of them.
In Ignix: Wrong formats are flagged per network, so you see that the image is fine for Facebook and not for Instagram before it goes anywhere.
The file is too heavy
Through the API it is 8 MB for images and 300 MB for video, and less for Stories. Instagram’s own app takes considerably more — which is why a video that uploaded fine from your phone can be refused by a scheduler.
In Ignix: Size is checked on upload rather than at publishing time, so you find out while you are still writing.
Your best hour, from your own account
Analytics has a “Best time to post” heatmap, weekday by hour, built from what your own posts earned and shown in your own timezone — not a table averaged over hundreds of thousands of accounts that are nothing like yours.
It is worth knowing what that measures, because two different numbers get called “best time to post”. Instagram’s own dashboard shows you when your followers are on the app. This shows what your posts actually got. Being awake and engaging are different behaviours, and the two answers sometimes disagree.
There is a longer piece on this — including how to read the grid, how much history it needs before it means anything, and why the hour matters less than the thing most guides skip.
More than one Instagram account, on one plan
The accounts in your plan are a pool and you spend them however you like. Three Instagram profiles on a three-account plan is fine; so is one Instagram, one TikTok and one LinkedIn.
This is worth checking wherever you end up, because it is not how the DM-automation tools work: in ManyChat, a second Instagram profile means a second ManyChat account with its own subscription.
Posting to several at once is one composer with the accounts ticked, and a preview per network so you can see what each one is getting — with its own caption if you want one — before it goes.
What happens after it publishes
A scheduler that stops at publishing leaves you the rest of the job. The comments arrive, the DMs arrive, and you answer them somewhere else.
Here the post that went out and the conversation it started are in the same place. A comment with a keyword can trigger an automatic DM — the classic “comment GUIDE and I will send it” — and the reply lands in the same inbox as everything else, where an AI agent can carry the conversation or hand it to you the moment it should.
That is also the part that matters more than the schedule. What people do with a post — watch it, send it to someone, save it, reply to it — carries it further than the minute it went out; the hour only changes who is awake to do any of it.
On the official API, with no password
Ignix publishes through Instagram’s official API. You authorise it from Instagram’s own site and we store no password and no access token — there is nothing in our database that could be used to get into your account.
No browser extension and no automation that pretends to be you tapping. Those are the shortcuts that get accounts restricted, and they are also why some tools stop working overnight when Meta changes something.
Longer read: the best time to post on Instagram — and what outranks it.
Questions people ask
Can I schedule Instagram Reels and Stories, not just feed posts?
Yes, both. Attach a single video and it publishes as a Reel; a Story you mark with a switch in the composer. Feed post, carousel and Reel you do not pick at all — Instagram works those out from the media, and the composer shows you which one you are going to get before you queue it.
Why do my scheduled Instagram posts fail?
The usual cause is an image outside the shape Instagram’s publishing API accepts for the feed, which is between 4:5 and 1.91:1 — including 3:4, the phone-camera default, which Instagram allows in the app but the API does not. The other usual causes are a file format it will not take (Meta documents JPEG as the only supported one; WebP and GIF do not go through), a file over the API size limit, or a post with no media at all, which Instagram refuses.
How many hashtags can I use on Instagram now?
Five, down from thirty since December 2025, and the five cover the caption and the first comment together. Instagram has not said what it does with any beyond that, so the safe reading is that they will not help you. Ignix counts the ones in the caption before publishing and offers to trim the extras back into plain words.
Can I connect more than one Instagram account?
Yes, and they come out of the same pool of accounts your plan includes rather than needing a separate subscription each. Three Instagram profiles on a three-account plan is a normal setup here.
Does it post automatically, or do I get a reminder?
It publishes automatically, through the official API. Reminder-based posting is what an Instagram scheduler falls back to when it cannot publish a format directly; here you do not have to be holding your phone at the scheduled time.
What is the best time to post on Instagram?
The honest answer is that it depends on your followers, and the useful version comes from your own history rather than from a published table. There is a full guide on how to find yours, why the free version Instagram gives you measures something slightly different, and why the hour is a smaller lever than it is usually sold as.
Schedule the next one, and answer what comes back
An Instagram content planner and post scheduler in one: a calendar for every account you run, a check before each post that knows what Instagram refuses, and the comments and DMs that follow in the same place. Unlimited contacts and messages on every plan.
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