How to Schedule Posts Across 9 Social Media Platforms in Under an Hour

How to Schedule Posts Across 9 Social Media Platforms in Under an Hour

Managing one social media platform is manageable. Managing nine is a different problem entirely. Each platform has different character limits, image dimensions, video requirements, and audience expectations. If you create and post manually for each one, you can easily spend three to four hours a day just on publishing.

posterly was built to collapse that time down. The unified composer lets you create one post and customise it for multiple platforms in the same window. The bulk upload feature lets you schedule dozens of posts at once from a spreadsheet. The calendar view gives you a single place to review and adjust everything before it goes live.

This guide covers exactly how to use these features so you can go from nothing to a full month of scheduled content in one sitting.

The platforms you can schedule to in posterly right now:

• LinkedIn
• X (formerly Twitter)
• Instagram
• Facebook
• TikTok
• YouTube
• Threads
• Pinterest
• Google Business Profile

The Problem With Platform-by-Platform Scheduling

If you have tried managing multiple platforms separately, you know the friction. You write a caption in one tab, copy it to another, resize the image, adjust the character count, then go back and do it all again for the next platform.

This is not just slow. It is also a common source of errors. Wrong image dimensions on Pinterest, a caption that is too long for X, forgetting to add hashtags for Instagram. These mistakes happen when you are moving fast across separate tools.

A unified composer solves this by letting you make these decisions once and apply them everywhere, with per-platform overrides where you need them.

Method 1: Using the Unified Composer

The Composer in posterly is where you build individual posts. It is the right tool when you are creating a small number of posts, testing a new campaign, or want to preview exactly how a post will look on each platform before scheduling.

Step 1: Open the Composer and Select Your Accounts

Go to Composer and click inside the account selector at the top. You will see all your connected accounts grouped by platform.

Select every account you want this post to go to. You can mix platforms freely. A single post can go to your LinkedIn, Instagram, and Facebook page at the same time.

Step 2: Write Your Base Caption

Type your main caption in the text area. This becomes the default for all selected platforms. The Composer shows a live character count for each platform, colour-coded so you can see instantly if you are over the limit somewhere.

For a 280-character limit on X, you will often need to trim. For LinkedIn, you have much more room. The Composer flags this in real time so nothing gets cut off silently.

Step 3: Customise Per Platform

Click on any platform tab below the main text area to write a platform-specific version of the caption. You might want to:

• Add hashtags for Instagram that you do not want cluttering the LinkedIn version
• Shorten the X version to fit within the character limit
• Add a more professional tone for LinkedIn
• Include a call to action specific to Facebook's audience

These per-platform overrides are optional. If a platform does not have a custom caption, it uses the base version automatically.

Step 4: Upload Your Media

Drag your image or video into the media area. posterly checks it against each selected platform's requirements and flags any issues. For example, if you select a horizontal image but TikTok needs vertical, you will see a warning before scheduling.

You can upload multiple images to create a carousel post on Instagram or LinkedIn. The Composer handles the ordering and formatting.

Step 5: Choose Your Time and Schedule

Pick your publish time using the date and time picker, or click Next Available to let posterly find the next open slot for your accounts.

If you want posterly to choose the best time automatically based on your audience activity, switch to AI Scheduler mode and describe when you roughly want the post to go out. The AI will handle the specific timing.

Click Schedule and the post is added to your calendar for all selected platforms simultaneously.

Method 2: Bulk Upload From a Spreadsheet

For a full month of content, the Composer works but it is slow. The faster approach is to plan everything in a spreadsheet first, then upload it all at once.

Step 1: Download the CSV Template

Go to Bulk Upload and download the template CSV. It has these columns:

Column	Required	Notes
caption	Yes	The post text
scheduled_at	Yes	Date and time in ISO 8601 format
account	Yes	Account username or ID
media_url	No	Publicly accessible image or video URL
post_type	No	text, image, video, carousel, or reel

Step 2: Fill Out Your Content Plan

Open the template in Excel, Google Sheets, or Numbers. Add one row per post. For posts going to multiple platforms, add a separate row for each platform with the same caption (or a customised version).

A week of content across three platforms might look like this:

caption,scheduled_at,account,media_url
"Our spring sale starts now. 20% off everything.",2026-04-14T09:00:00,@myinstagram,https://cdn.example.com/spring-sale.jpg
"Our spring sale starts now. Link in bio for 20% off.",2026-04-14T09:05:00,@mylinkedin,https://cdn.example.com/spring-sale.jpg
"Spring sale is live. 20% off all products today.",2026-04-14T09:10:00,@myxaccount,

Notice the slight caption variations for each platform and the staggered times. Posting to all platforms at the exact same second is not necessary and staggering by a few minutes avoids any rate limiting.

Step 3: Upload and Preview

Back in posterly's Bulk Upload screen, upload your CSV. posterly will:

1. Parse each row and validate the data
2. Check captions against platform character limits
3. Flag any missing required fields
4. Show you a preview of all posts before anything is scheduled

Review the preview carefully. This is your last chance to catch errors before they go into the queue.

Step 4: Confirm and Schedule

Once the preview looks correct, click Confirm and Schedule. All posts are added to your calendar at once.

Open the Calendar view to see everything laid out visually. You can still edit, reschedule, or delete individual posts at this stage.

Reviewing and Adjusting Your Calendar

The Calendar view is where you get a monthly overview of everything scheduled. Three views help with different tasks:

Calendar view shows posts on a day-by-day grid. Use this to spot gaps in the schedule or days that are overloaded with posts. You can drag and drop posts to different dates if the distribution looks off.

List view shows posts in chronological order. Use this to review captions in sequence, especially useful for checking that a campaign flows logically from one post to the next.

Table view lets you filter and sort posts by platform, label, status, or date. If you want to audit all your Instagram posts for the month in one go, this is the view to use.

Checking Platform Coverage

One common issue when scheduling at scale is accidentally forgetting a platform for a particular week. In Table view, filter by platform and check that each one has posts going out regularly.

If you use Labels to tag posts by campaign or content pillar, you can also filter by label to make sure each campaign is properly distributed across your accounts.

Platform-Specific Things to Watch

Each platform has quirks that affect how posts are built. Here are the most important ones to keep in mind when scheduling at scale:

Instagram requires media for most post types. Text-only posts are not supported on feed posts. Make sure every Instagram row in your bulk upload has a media URL.

TikTok requires vertical video for most post types. If you are posting video content, use a 9:16 aspect ratio.

LinkedIn supports documents (PDF carousels) as a post type. If you are sharing a multi-page document, use the LinkedIn-specific composer option rather than a standard image post.

Pinterest is image-first and benefits from vertical (2:3) images. Pinterest posts also benefit from keyword-rich descriptions rather than short captions.

Google Business Profile has unique post types for events, offers, and standard updates. The Composer surfaces these options when Google Business Profile is selected.

YouTube posts in posterly are for community posts rather than video uploads. Video publishing to YouTube has its own workflow in the Composer.

Saving Even More Time With Recurring Posts

If you have content that you want to post on a regular schedule, such as a Monday tip, a Friday recap, or a monthly product highlight, use Recurring Posts instead of scheduling each one manually.

In the Composer, enable the Recurring toggle and set the frequency: daily, weekly, or monthly. posterly will automatically reschedule the post after each publish so it stays active indefinitely without any action from you.

This is particularly useful for evergreen content that stays relevant regardless of when it is seen.

Frequently Asked Questions

Can I schedule the same post to all 9 platforms at once?

Yes. In the Composer, select all 9 accounts at once. You can write a base caption that all platforms share, and then add platform-specific versions for any that need a different length or tone. One click schedules it to all selected accounts.

What happens if a post fails to publish on one platform but succeeds on others?

posterly tracks the publish status of each post per platform independently. If one platform fails (for example, due to an expired token), the others still go live. You will see the failure flagged in your calendar and can retry from there.

Is there a limit on how many posts I can bulk upload at once?

The limit depends on your plan tier. Most plans support large batch uploads. You can check the specifics on the posterly pricing page.

Can I edit a scheduled post after it has been added to the calendar?

Yes. Click any post in the Calendar or List view to open it. You can edit the caption, swap the image, or change the scheduled time up until it publishes. Changes are applied immediately.

How do I handle different timezones for different accounts?

If you are managing accounts for clients in different timezones, you can set a per-client timezone in your workspace settings. The calendar and time picker will automatically adjust to show times in the correct timezone for each client.