Writing and publishing

The composer is one draft: a thread of cards, the accounts it goes to, and a Publish button with a schedule option next to it. Everything here happens in the browser; the same actions are available to scripts through the API, and to AI agents through its MCP server.

Drafts save themselves

A draft is saved as you type, and Cmd/Ctrl + S saves it on demand. Drafts are listed under Posts → Drafts, where Edit Post reopens one and Remove deletes it. The trash button in the composer discards the draft you are on, after asking.

The top right of the composer says where the draft stands: Saving…, Saved, or Not saved with a Retry button. A failed save is retried on its own until it goes through. Switching to another tab or app saves at once, so a phone that closes the browser in the background does not cost you the last thing you typed.

To start another post mid-thought, press Write at the top right. It saves the post you are on and opens a blank one; a draft lands in Posts → Drafts, and a scheduled post keeps its time. On an empty composer Write is hidden, since there is nothing to put away.

A thread is a list of cards

Each card is one post, with its own character counter and its own images. The counter uses the strictest limit among the accounts you picked, counted the way that platform counts: graphemes for most, while Mastodon and X count every link as 23 characters, and X also counts CJK characters and each emoji as 2.

Bluesky posts a link the way its own app does: the post shows the site and the start of the path, such as example.com/blog/2026/11..., and the link still opens the full address. The counter counts that shorter text, so a long link no longer uses up most of Bluesky’s 300 characters. An account with compact links on shows only the site, example.com/.... A post going to several Bluesky accounts is counted for the one whose links come out longest, so it fits on all of them. A Bluesky account connected through Zernio gets the link as typed, and counts it in full.

• + Thread adds a card; the × on a card removes it.
• Type --- in a card to split it there. The text after the marker moves into a new card below; several markers make several cards.
• Paste a long draft and it is split for you: into a thread that fits that same strictest limit. Paste text with --- on lines of their own and it splits on those instead.
• Alt + ↑ / ↓ moves the card you are typing in up or down the thread.

LinkedIn and Instagram have no threads: a thread sent there is flattened into one post. The limits for every platform are in OAuth apps → Platforms.

An X account on a paid plan can post up to 25,000 characters in one post (how CogSend knows). The counter still follows the strictest account you picked, so adding a free X account holds the whole post to 280. X shows about the first 280 characters of a long post and folds the rest behind Show more, and the card says so once the text passes that point. If X refuses a long post, it fails without a retry and that account drops back to 280; the message says how to turn long posts on again.

Images and alt text

Each card takes up to four images, shown large in the card the way they will be laid out: one image at its own shape, two to four in a grid. Add them with the image button, by pasting, or by dropping files anywhere on the card; pick more than fit and the first ones are attached, with a note saying how many were left out. Its buttons sit in the top corner, on hover or always on a phone: ALT (amber until it has a description) opens the alt-text field (“Describe this image…”); fill it in and it goes out with the image on platforms that support it. The × removes the image. Size and format limits differ per platform — Bluesky takes 2 MB, X 5 MB, and LinkedIn rejects WebP — and are checked again when the post is published. An image a selected account would refuse, for its size or type (a WebP on LinkedIn, anything but JPEG or PNG on Threads), is named in a line under the card, with a link to uncheck that account.

A larger image is shown from a lighter 1280 px copy your browser makes when you attach it, in the composer and in Posts; the original is what gets published. Click an image to see it whole, with its alt text: the arrows, arrow keys or a swipe move between the images of a post, and Esc or a click beside the picture closes it.

Your media, the button beside Add Image on each card, lists the images and videos already used in your posts, whether drafts, scheduled or published, the most recently attached first. Pick one or more and press Attach: the file is not stored again, and it comes with the alt text it was last attached with, which you can change for this post without changing the others. Anything that can’t go on the card is greyed out, such as a video beside other media or a fifth image. A file leaves the list once the last post using it is deleted. The list shows a small copy your browser makes when you attach an image, and a still of a GIF; an image attached before 1.30 shows as it does in the composer.

An image over 2 MB is shrunk in your browser before it uploads, so a pasted screenshot fits every platform: it is scaled down to 2560 px on the long edge, kept as PNG when that is enough and re-encoded as JPEG when it is not. GIFs and animated WebP are left as they are, since shrinking them would drop the animation. If an attached image is still over a selected platform’s limit, a line under the image names the platform, with a button to uncheck it, and Publish and Schedule stop until it is resolved.

Instagram

Every Instagram post needs a photo or a video, so with an Instagram account selected a text-only post shows Instagram needs a photo or video on the first card, with Uncheck Instagram, and Publish and Schedule stop until you attach something or uncheck it. The other accounts are not held to it.

One photo goes out as a photo post, two to ten as a carousel, and a video on its own as a Reel. Instagram takes JPEG photos from 4:5 tall to 1.91:1 wide; a PNG or WebP is sent through a full-size JPEG copy your browser makes when you attach it, and an image without one, attached before Instagram support or too large to copy within Instagram’s 8 MB, asks to be attached again or as a JPEG. With the Images binding, the server makes a missing copy itself when the post is scheduled or published. GIFs, a video beside photos, and more than ten photos are refused for Instagram the same way, with a line naming the problem. A thread is flattened into one caption of up to 2,200 characters and 30 hashtags.

A URL in a card shows the link preview it will produce, while you write.

Video

A card takes one video (MP4, MOV or WebM) and nothing else beside it; a thread can have a video on each card. Your browser prepares it before it uploads: a file every platform already takes goes up as it is, and anything else, such as a phone’s HEVC video, a 4K clip or a frame rate over 60, is converted to MP4 (H.264 with AAC sound) at most 1920 pixels on the long edge. The card shows the video at its own shape, with Reading, Converting and Uploading and the progress along its bottom edge, and Cancel stops it. Once it is up, the video shows its cover with a play button and its length, and loads only when you press play. Videos up to 300 MB go up in parts, so a slow connection only resends the part that failed. While a video is converting or uploading, CogSend keeps you on the page until it is done or you cancel it, and closing the tab makes the browser ask first. A browser that can’t convert the file says so; export it as MP4 (H.264) and attach it again.

When every selected platform takes the video, nothing more is shown. When one doesn’t, a line under the video says why, one line per platform: X takes 2:20 unless the account has X Premium, Threads 5 minutes, Bluesky 10, Instagram 15, LinkedIn 30. Uncheck on the line drops that platform’s accounts, and the accounts button in the dock and the account itself carry a red dot until it is resolved. Publish and Schedule stop on the first platform that would refuse it; trim the video or uncheck that account. A Mastodon account is held to the limits its server reports, which CogSend reads when you connect the account and again every day, so a server that raises its limits is followed within a day.

COVER, among the buttons on the video, picks the frame shown before it plays: scrub to a moment and Use this frame, or Upload image. Mastodon, LinkedIn and Instagram show it; X, Threads and Bluesky choose their own frame. Until you pick one, the frame one second in is the cover, and it is also what Posts shows. ALT describes the video, as for an image.

Platforms process a video before it can be posted, which can take minutes. CogSend uploads and waits for up to 20 seconds of the publish, then hands the rest to the next tick: the result says the platform “is processing the video” and that it publishes on its own, and Posts marks it Processing. A large video to X or LinkedIn is sent over several ticks the same way, carrying on from the last part sent. So closing or reloading the tab right after Publish loses nothing. Waiting uses none of the five attempts. A video still not ready after 45 minutes fails, and Retry starts it again.

Quote posts on X

X shows a post as a quote when its text ends with a link to another X post. With an X account selected, paste such a link at the end of a card and it turns into a quote card: the author and text of the quoted post, the way X will show it. The link leaves the text box but stays saved at the end of the text, which is what X needs. A link you type by hand moves into the card once you click away from the box, and the × on the card removes the quote.

• X quotes only a link at the very end. A link to an X post anywhere else in the text stays a plain link, and the card says so, with a button to quote that post instead.
• A card quotes one post. Another X link pasted into it stays in the text as a plain link, so nothing is lost; its button swaps the two. To quote several posts, give each its own card with + Thread.
• The quote button in a card’s tools lists your recent published X posts, so you can quote one without copying its link.
• On Global, the other selected platforms get the same text, link included, and the card names them. Only on X keeps the quote for X alone: X gets its own tab with the quote, and the others get the text without the link. On the X tab, Share with all gives them the link again. A card holding only the quote can’t be split this way.
• On Bluesky and LinkedIn, a link to an X post gets a card with the post’s author and text.
• X bills a post that contains a link at $0.20 instead of $0.015, and a quote is such a post.

Global, and a tab per platform

The Global tab is the post every account gets. With more than one account selected, Add override… adds a tab for one platform, where you can rewrite the text for that platform alone — shorter for X, longer for LinkedIn — without touching the others. An override tab is unlinked from Global from then on; its reset button re-syncs it to the Global text.

Options, next to the tabs, holds the settings only some platforms have, with a section for each selected platform that has any. The chip lists what is set, such as Options · Unlisted · AI Tools, and turns red while a setting is wrong.

• Mastodon: the visibility (Public, Unlisted, Followers, Direct) and an optional content warning.
• Threads: an optional topic tag, the single clickable topic Threads shows on a post. It takes up to 50 characters, without . or &, and a # in front is dropped. In a thread it goes on the first post.

Choosing destinations

The accounts button in the dock (N selected) opens the list of connected accounts. Tick the ones this draft goes to; Clear all empties the list. An account that needs reconnecting is marked, and Accounts is where you fix it.

Publish now, or schedule

Publish hands the draft to every selected account and empties the composer at once, so you can start the next post while it goes out. The result arrives as a message wherever you are in the app, updated as each account answers (“Published to Mastodon · still sending to Threads”) and ending with Published to 3 destinations, or which account failed and why, with a link to the post in Posts. A failure also puts a red dot on the menu at the top left, beside Posts, until you open it. By default Publish asks first, with a Confirm Post step; tick Publish without asking next time to skip it in this browser, and turn the question back on under Settings → Preferences → Ask for confirmation before publishing. Cmd/Ctrl + Enter publishes from the keyboard.

The calendar button next to it schedules instead: either Publish in an offset of minutes, hours or days (one hour by default), or a Specific Date and time in your own timezone. Opening a scheduled post again with Edit Post starts on the time it is already set for, so confirming without a change keeps it. A scheduled post waits in Posts → Scheduled until a tick publishes it. Scheduling goes to exactly the accounts ticked: untick one and schedule again, and its earlier time is cancelled.

Opening a scheduled post shows, above the text, when and where it goes out. Edits save as you type, and what is saved when the time comes is what gets posted. Ticking or unticking accounts doesn’t change the schedule by itself: the post says which accounts differ, and Update schedule applies them. Change time opens the schedule at its current time, and Unschedule turns the post back into a draft. Publish now sends it straight away instead of at its time, and any account you unticked is unscheduled, so it doesn’t post later either. Deleting it with the bin means it won’t be published. A few minutes before the time, the post says so; while it is being sent, editing pauses until the result is in. A post that went out on some accounts, failed on others or is retrying says so in one line, with a link to the details in Posts.

Once a post is scheduled or handed off to publish, the composer empties for the next one and the message links to it in Posts. A post you opened from Posts takes you back there instead. Publishing again to an account that already has the post sends nothing, and the message says so.

If some accounts fail, the message says which and why, and Posts → Failed has a Retry for each. A scheduled post that hits a retryable failure (a rate limit, a platform timeout) tries again on its own, backing off from one minute up to thirty — five attempts, then it stops in Failed. See Posts and Insights.

Where to go next

• Posts and Insights — what happens to a post after you publish or schedule it.
• Connecting accounts — adding the accounts the composer publishes to.
• OAuth apps — every platform’s limits on text, images and threads.