What Is a Social Media Caption Generator?
A social media caption is the text published with a post: the words under an Instagram photo, the body of a LinkedIn post, the description of a Pin. A social media caption generator is a tool that writes that text for you, and an AI social media caption generator is one that uses a language model to do it, which today means nearly all of them. You give it something to work from (a topic, a picture, a link or a set of facts) and it returns a caption sized for one network or for several.
The tools differ in what they start from. A caption box takes a topic and a tone: Hootsuite's free tools page lists a caption generator with versions for Instagram, LinkedIn, Facebook and Threads. A caption writer inside an editor reads the picture: Adobe Express's Caption Writer looks at the first image of a post, takes an optional description, and uses 1 generative credit each time you select Generate. A chat assistant writes whatever you ask for from whatever you paste in.
Spreadcast starts from your App Store listing. It designs a post when your app ships an update, receives a new 5 star review or passes a rating milestone, and it writes a separate caption for each of 8 networks as part of that post. For an app, that removes the step every other caption generator leaves with you: deciding what to post and typing the facts in. For captions about anything else, use one of the other three kinds. All of them are compared further down this page.
Caption Limits by Network: Characters, Hashtags and Links
Every number comes from the network's own help or developer page, opened on October 11, 2026. Where a network publishes no limit, the table says so and does not repeat numbers from third party blogs.
| Network | Characters | Hashtags | Links |
|---|---|---|---|
| 2,200, per Meta's media reference. | Up to 5 on a post, per Instagram's hashtag help page. Meta's media reference still lists 30. | The caption field takes text, hashtags and @ mentions. The reference has no link field for a feed post, so point people to the link in your profile. | |
| 3,000, per LinkedIn's help page on posts. | No limit published. LinkedIn's Pages best practices suggest picking 3 to 5. | Allowed in the post text. | |
| X | 280, per X's character counting rules. Each emoji counts as 2. X Premium subscribers can post up to 25,000. | No limit. X's hashtag help page recommends no more than 2 per post. | Allowed. Every URL counts as 23 characters, whatever its real length. |
| No limit published. Meta's Pages API guide gives no maximum for the post message. | No limit published. Facebook's hashtag help page says a hashtag becomes a clickable link. | Allowed. The Pages API has a link field that turns the post into a link post. | |
| TikTok | Photo post: title 90, description 4,000, per TikTok's photo post reference. Video caption: 2,200, per the direct post reference. | No number published. The direct post reference says # and @ are matched inside the caption. | Not covered in either reference. |
| Threads | 500, per Meta's Threads posts guide. | One topic tag per post, 1 to 50 characters. If a post has several, the first valid one counts. | 5 or fewer per post. Meta has enforced this through the API since December 22, 2025. |
| Title 100, description 800, per Pinterest's product specs. The first 40 characters of the title may show in feeds. | Not mentioned in the specs. | A Pin can carry a link. The specs page describes how Pinterest highlights links included in a Pin. | |
| Bluesky | 300, per the Bluesky post schema. | No limit in the text. The schema allows up to 8 extra tags outside it. | Allowed. Bluesky's posts documentation describes links and mentions as rich text markup, and up to 4 images per post. |
Two of these moved recently. Instagram's help page now says 5 hashtags where older guides say 30, and Pinterest's creative best practices say descriptions run up to 500 characters while its specs page says 800. When two official pages disagree, write to the lower number.
How One Post Should Read on Each Network
The limits explain why one caption cannot go everywhere. A 2,200 character Instagram caption does not fit in 280 characters on X, and a block of 5 hashtags does nothing on Threads, where a post takes one topic tag. The picture can stay identical. The words should change. Our table of social media character limits has the numbers for every network. If you are still deciding which networks deserve the effort, start with how to promote an app on social media.
Instagram
Lead with what changed, in the first sentence. Use the middle for one or two details and end with one ask. Keep hashtags to 5 or fewer and send people to the link in your profile, since the caption has no link field. An Instagram caption generator that returns 30 hashtags is working from old rules.
LinkedIn
Write as the person who built it. Say what you shipped, why, and what you learned or who asked for it. You have 3,000 characters, and three short paragraphs is plenty for an update. Add 3 to 5 hashtags at the end, as LinkedIn's own guide suggests.
X
One point per post. With 280 characters and 23 of them spent on the link, you have room for the version number, the main change and one detail. Use 2 hashtags at most, or none.
Facebook
Plain sentences and a link. Write for people who already follow the Page and may be less technical than your X audience: say what the change does for them.
TikTok
A still image post has a title of 90 characters and a description of up to 4,000. Put the hook in the title, because that is the short field. Use the description for the details and a few hashtags.
Threads
Short and conversational, within 500 characters. Pick one topic tag that names the subject, such as Plant Care, and consider ending with a question. Answering the replies is your job, and no tool should do it for you.
Pinterest
Write the title for search: what the Pin helps someone do, in words they would type. Pinterest's product specs say the description does not show in the feed and is used to judge relevance, so describe the app and the use case in full sentences. More in Pinterest for app founders.
Bluesky
300 characters and a plain, human tone. Skip the hashtag block. One sentence on what is new and one on why it matters is enough.
How to Write a Good Caption: First Line, Length, Keywords and Call to Action
Most advice on how to write a caption is opinion. These six points each rest on something a network or a published study says, so you can check them.
Put the Point in the First Line
Feeds cut captions short, so the opening words carry the post. Pinterest says it outright: a Pin title holds up to 100 characters, and Pinterest's creative best practices say the first 40 are the ones most likely to appear. Write the first sentence so it works with nothing after it: what changed, and for whom.
Keep It Short Unless the Detail Earns the Space
Socialinsider's caption length study looked at 9.1 million Instagram posts from 82,952 business pages, published from January to July 2023, and found that captions under 30 words usually had a higher engagement rate than longer ones. The data is from 2023 and observational, so treat it as a default. Say it in two or three sentences, and go longer only on LinkedIn or when the story is the post.
Write the Words People Search
Instagram search matches text. In Instagram's explanation of how search works, Adam Mosseri advises putting relevant keywords and hashtags in the caption, and not in the comments, if you want a post to be found. TikTok's Creator Academy article on search, updated in August 2026, makes the matching point: accurate wording helps, and a caption loaded with loosely related keywords can work against you.
End With One Call to Action
Apple's App Store marketing guidelines tell developers to always include a call to action to download the app. In a caption that is one closing line: update on the App Store, try the new widget, or tell us which plant goes on it first.
Ask a Question You Will Answer
Buffer's 2026 engagement report, published in March 2026, compared each account with its own baseline and found higher engagement on posts where the account replied to comments: 42 percent higher on Threads, 30 percent on LinkedIn and 21 percent on Instagram. Buffer says this does not prove cause, since strong posts attract more comments to reply to. A question in the caption is still the cheapest way to start those comments.
Use Plain Language
The US government's Section 508 guidance on social media recommends plain language for public posts: active voice, short sentences, no jargon. For an app that means the user's word for the feature, such as "your next watering day", and never the name of the framework behind it.
Seven Caption Formulas for App Posts, With an Example for Each
If you write captions by hand, or want to judge what an AI caption generator gives you, these seven sentence orders cover updates, reviews, milestones and features. Each opens with the change in the user's words, adds one proof and ends with one ask. One proof is enough: three reads like release notes, and app release notes examples are a different format. Then fit the result to the network: cut to the limit, set the hashtags to that network's number and move the link to where that network puts links. The examples are for Fernwise, a made up plant care app that also appears in the tables below.
| Formula | When to use it | Example |
|---|---|---|
| Change, proof, ask | Any update with one headline change. | Your next watering day now sits on your Home Screen. The widget refreshes every morning. Update Fernwise on the App Store. |
| Problem, fix, where | A bug fix, or a feature that removes an annoyance. | Reminders used to drift when you changed time zones. Fernwise 3.2 keeps them on your home time. The update is on the App Store now. |
| Before and after | Speed, size or accuracy improvements. | The light meter took 6 seconds. It now takes about 2. Same phone, same window. |
| Number first | Milestones and ratings. | 1,000 ratings and a 4.8 average. Thank you for every one of them. |
| Question first | Threads, Facebook, and feature posts in a quiet week. | Which plant in your house gets forgotten most? Put it on the Fernwise widget and it will not be. |
| Thank you, reason, next | Review posts and milestone posts. | Thank you for the 5 star rating this week. Ratings are how new plant owners find Fernwise. Next up: a calendar view. |
| Tip in three steps | A feature post, and any Pinterest description. | Open the light meter, point your phone at the window, wait 2 seconds. Fernwise tells you if the spot suits low, medium or bright light plants. |
15 Example Captions for an App Update, Review, Milestone and Feature
These social media caption examples are for Fernwise on the day it shipped version 3.2. Swap in your app, your numbers and your link. The X and Bluesky examples fit inside 280 and 300 characters.
| Post | Network | Caption |
|---|---|---|
| App update | Fernwise 3.2 is out. Your next watering day now sits on your Home Screen, so you can check it without opening the app. The light meter reads in about 2 seconds, and reminders stay on time when you travel. Update from the link in our profile. #PlantCare #Houseplants #PlantApp | |
| App update | We shipped Fernwise 3.2 today. The most requested change since launch was a Home Screen widget, so that is the headline: your next watering day, visible at a glance. We also cut the light meter reading from 6 seconds to about 2 and fixed reminders that drifted after a time zone change. Thank you to everyone who wrote in about that bug. The update is free on the App Store. #IndieDev #PlantCare #ProductUpdate | |
| App update | X | Fernwise 3.2 is live. New Home Screen widget shows your next watering day. Light meter is 3 times faster. Travel no longer breaks reminders. (App Store link) |
| App update | Threads | Fernwise 3.2 is out with a Home Screen widget for your next watering day. Which plant in your house goes on it first? Topic tag: Plant Care |
| App update | TikTok | Title: Your watering day, now on your Home Screen. Description: Fernwise 3.2 adds a widget, a faster light meter and reminders that survive time zones. #PlantCare #PlantTok |
| Review, rating only | Another 5 star rating for Fernwise this week. Thank you. If the app has saved one of your plants, a rating on the App Store helps other plant owners find it. #PlantCare #Houseplants | |
| Review, quoted with permission | A review from this week that made our day: 'I have kept a fern alive for a full year for the first time.' Shared with the reviewer's permission. We are a small team with one app, and notes like this are why we keep shipping. #IndieDev #PlantCare | |
| Review, rating only | Fernwise just received a new 5 star rating on the App Store. Thank you to everyone who takes a minute to rate the app. It is the main way new plant owners find us. (App Store link) | |
| Review, rating only | Bluesky | New 5 star rating for Fernwise today. Thank you, whoever you are. Your pothos is in good hands. |
| Milestone | X | 1,000 ratings on the App Store and a 4.8 average. Thank you to every one of you who rated Fernwise. (App Store link) |
| Milestone | Threads | Fernwise just passed 1,000 ratings with a 4.8 average. We are two people and one very thirsty office fern. Thank you. Topic tag: Indie Apps |
| Milestone | 1,000 ratings and a 4.8 average. When we launched Fernwise we hoped a few hundred people would try it. Thank you for every rating and every note you sent. (App Store link) | |
| Feature | Title: How to Tell if a Room Is Bright Enough for a Fiddle Leaf Fig. Description: Point your phone at the window and the Fernwise light meter tells you if the spot suits low light, medium light or bright light plants. Free plant care app for iPhone with watering reminders and a light meter. | |
| Feature | Not sure if that corner gets enough light? Open the light meter in Fernwise, point your phone at the spot and get an answer in about 2 seconds: low, medium or bright. No extra hardware. #PlantCare #Houseplants #PlantTips | |
| Feature | Bluesky | Fernwise tip: the light meter works in any room. Point, wait 2 seconds, and it tells you which of your plants would be happy there. |
Two Apple rules apply to the review and milestone rows. Apple's ratings and reviews guidance says a rating used in marketing has to match the app's current rating, and a customer review may be used only if the reviewer gave permission. Our App Store marketing guidelines summary covers the rest.
10 More Caption Examples: First Launch, Bug Fix, Quiet Week and Rating Average
Same app, four other moments: the day Fernwise first went live, a small fix release (version 3.2.1), a week with no update, and a rating average worth sharing. The X captions stay under 280 characters with the link counted, Bluesky under 300 and Threads under 500.
| Post | Network | Caption |
|---|---|---|
| First launch | Fernwise is on the App Store today. Add your plants, and the app tells you when each one needs water and whether its spot gets enough light. Your first 5 plants are free. Find it through the link in our profile. #PlantCare #Houseplants #NewApp | |
| First launch | Today we launched Fernwise, a plant care app for iPhone. Two of us built it over 11 months because we kept losing the same fern. It does two things: it reminds you when each plant needs water, and it measures the light in any spot with your phone camera. The first 5 plants are free. If you try it, tell us what is missing. Fernwise is available on the App Store. #IndieDev #ProductLaunch #PlantCare | |
| First launch | X | Fernwise is live on the App Store. Watering reminders for every plant you own, plus a light meter that uses your phone camera. First 5 plants free. (App Store link) |
| First launch | Title: Plant Watering Reminder App for iPhone. Description: Fernwise reminds you when each houseplant needs water and measures the light in any room with your phone camera. Add a pothos, a monstera or a fiddle leaf fig and get a schedule for each. Free for your first 5 plants. | |
| Bug fix update | X | Fernwise 3.2.1 fixes the widget that showed yesterday's date for some of you. Thanks to everyone who sent a screenshot. (App Store link) |
| Bug fix update | Threads | Small Fernwise update today: the widget no longer shows yesterday's date after midnight. If it still looks wrong on your phone, reply here and we will look. Topic tag: Plant Care |
| Quiet week, feature tip | Going away for a week? Open any plant in Fernwise, tap Share Schedule, and send your plant sitter the watering days. They do not need the app. (App Store link) | |
| Quiet week, feature tip | TikTok | Title: Check the light before you buy the plant. Description: Hold your phone where the plant will live. The Fernwise light meter reads the spot in about 2 seconds and lists the plants that suit it. #PlantCare #PlantTok |
| Rating average | Fernwise holds a 4.8 average on the App Store as of this week. We read every review, including the 3 star ones, and two of those are why the widget exists. Thank you. #PlantCare #Houseplants | |
| Rating average | Bluesky | Fernwise sits at 4.8 stars on the App Store as of this week. Thank you to everyone who rated it. Now go check your fern. |
A rating in a caption goes out of date, which is why both rating rows say "as of this week". Longer sets for these moments are on the pages of app launch announcement examples and app update announcement examples.
How Many Hashtags to Use on Each Network, With an Example Set
Hashtag rules now differ between networks more than character limits do. The counts are the networks' own, from the pages linked in the limits table. The last column shows a complete set for Fernwise, so you can see how little is needed.
| Network | How many, and where | Example set |
|---|---|---|
| 5 or fewer, in the caption. Instagram's hashtag help page says a comment carrying more than 5 tags will not post, and Instagram's search guidance says to put tags in the caption, not the comments, for a post to be found. | #PlantCare #Houseplants #PlantTips | |
| 3 to 5 that name your field, at the end of the post. | #IndieDev #PlantCare #ProductLaunch | |
| X | 2 at most, or none. | #PlantCare |
| Threads | One topic tag per post. | Plant Care |
| TikTok | A few that describe the post. TikTok's Creator Academy article on search says a long list of hashtags does not lift a video in search. | #PlantCare #PlantTok |
| None needed. Facebook publishes no count, and a hashtag there becomes a clickable link. | #PlantCare, or nothing | |
| None. The product specs do not mention hashtags, so put the search words into the title and description as sentences. | "Plant watering reminder app" in the title | |
| Bluesky | None in most posts. One short tag in the text is fine. | #PlantCare, or nothing |
Capitalize each word in a hashtag made of several words. Section 508's social media guidance explains that a screen reader may otherwise read the tag as one unclear word. #PlantCare is read as two words. #plantcare may not be.
How Many Hashtags on Instagram Is Too Many?
Six. Instagram now takes at most 5 hashtags on a post or a Reel, per Instagram's hashtag help page. Social Media Today reported the change on December 18, 2025: Instagram said it would gradually cap captions at five after testing limits for about a year, with many users held to three in the latest test. Its stated reason was that fewer, targeted hashtags work better than many generic ones.
So how many hashtags on Instagram is good? Between 3 and 5, each one specific. Adam Mosseri, who runs Instagram, said in February 2025 that hashtags do not work to increase reach, and in May 2025 that they are a good way to tell people what a post is about, according to the same report. Read that as labels, not as a growth lever. For an app, one tag for the topic (#PlantCare), one for the audience (#Houseplants) and one for the kind of post (#PlantTips) cover it.
Is it better to put Instagram hashtags in the caption or the comments? The caption. Instagram's explanation of how search works says keywords and hashtags belong in the caption, not in the comments, if you want the post to be found. A first comment full of tags was a workaround for the old limit of 30 and now runs into the same cap of 5.
This is also how to judge a caption generator with hashtags. If it returns 15 or 30 tags for Instagram, it was built for the old rule, and you will have to cut its output before the post will go through. Spreadcast sets each network's count when it writes the caption: 3 to 5 on Instagram, at most one topic tag on Threads and none on Pinterest.
Emoji, Tone and Apple's Wording Rules for App Captions
Three small things decide whether a caption reads as written by the person who made the app.
Emoji: Few, and at the End
On X every emoji counts as 2 characters toward the 280. Screen readers announce each emoji by name, so the Section 508 guidance asks you to limit them, avoid several in a row and place them at a natural stopping point, such as the end of a paragraph. One at the end of a caption is plenty for a product post.
Tone: The Maker, Talking to a User
Write in the first person, as the team that shipped it: "we fixed", "you can now". Give the number. A reader believes "reads in about 2 seconds" and skips "blazing fast". Shift the register by network (a little story on LinkedIn, a little play on Threads) while the facts stay identical.
Say Available on the App Store
Apple's marketing guidelines accept "available on the App Store" and "can be downloaded from the App Store". They rule out "at the App Store", the word "downloadable" and any extra descriptor in front of the store's name.
Name the Device the Way Apple Does
Put the app name first and the product after it: Fernwise for iPhone. The same guidelines ask for Apple product names in the singular, rule out "smartphones" and "tablets" as words for Apple devices, and ask you to avoid naming the operating system in marketing copy. That is why the examples here use #PlantApp where older captions would name the system.
Common Caption Mistakes on App Posts
Each of these can be checked in a minute before you publish.
The Same Caption on Every Network
A caption written for LinkedIn's 3,000 characters does not fit in 280 on X or 300 on Bluesky, and a block of 30 hashtags (the old Instagram ceiling) now breaks Instagram's limit of 5. Write the short version first, then expand it for the networks with room.
A Link in the Wrong Place
Each network puts links somewhere different. On Instagram, send readers to your profile, which holds up to 5 links per Instagram's help page on profile links. On X the link costs 23 characters. On Threads a post takes 5 links at most. On TikTok, TikTok's help page on profile links says a general account needs 1,000 followers before it can add a website, so write the app's name clearly enough to search for.
A Review or Rating Apple Would Not Allow
Quoting a reviewer needs that reviewer's permission, and a star average has to match the current one. Both rules come from Apple's ratings and reviews guidance.
Keyword Stuffing
TikTok's Creator Academy warns that unrelated keyword text added to a video can get it flagged as spam, and that a caption overloaded with loosely related keywords or hashtags can work against you. Two or three accurate phrases do the work.
A Caption With No News
"Bug fixes and improvements" gives a reader nothing to repeat. If the release has no change you can name, skip the announcement and post a feature tip that week.
Five Ways to Write Captions for an App, Compared
We make Spreadcast, so it is listed first, and for an app on the App Store it is the way that leaves you the least to do: it designs the post, writes the caption for each network and publishes both. The other four write text for a post you still have to plan, make and publish. Prices were checked on October 11, 2026.
| Way | What it starts from | What you still do | Cost |
|---|---|---|---|
| Spreadcast | Your App Store listing: release notes, ratings, reviews, screenshots and icon. | Paste one link, connect your accounts, then tap approve or switch on full autopilot. | Free plan drafts every post for you to download. Pro is $29 a month flat, with design, captions and publishing to 8 networks included. See pricing. |
| A chat assistant (Claude, ChatGPT) | Whatever you paste in: release notes, a rough idea, an old caption. | Paste the facts each time, ask for each network, check limits and hashtag counts, make the image, publish. | Claude's pricing page lists a free plan and Pro at $20 a month billed monthly. ChatGPT's pricing page lists a free plan with unlimited text chats. |
| A free caption tool (Hootsuite, Buffer) | A topic, a tone and a network you pick. | Type the facts in, run it once per network, make the image, publish. Buffer's free post creator gives up to 5 posts a day in the browser without an account, and every retry counts. | $0. |
| A caption writer inside an editor or scheduler (Adobe Express, Later) | The post you already designed there. Adobe's reads the first image and a short description. | Design the post, generate, edit, schedule. | Adobe Express Premium is $9.99 a month with 250 generative credits, 1 per caption. On Later's pricing page a caption costs 1 AI credit, and Starter at $25 a month billed monthly includes 5. |
| By hand | Your own notes. | All of it: 8 networks means 8 captions per post, each counted and tagged. | $0 and your time. |
If you already write captions in Claude or ChatGPT, you can also connect your assistant to Spreadcast through its MCP server. It then designs the post in your app's brand, writes a caption for each network inside that network's limit and saves it as a draft for you to approve.
Can ChatGPT Write Instagram Captions?
Yes, and on the free plan: ChatGPT's pricing page lists a free tier with unlimited text chats. The caption it writes is only as good as the facts you give it, though. ChatGPT does not know what your app shipped this week, how many ratings it has or which network the caption is for, so a request like "write a caption for my app update" gets a generic paragraph with a row of hashtags.
Give it the facts and the rules in one message. A prompt that works: "Write an Instagram caption for Streakly, a habit tracker for iPhone. Version 4.1 adds a weekly review screen and a Home Screen widget for today's streak. Audience: people building a morning routine. Put the change in the first sentence, keep it under 40 words, end with one call to action that says available on the App Store, and add no more than 3 hashtags." Then ask for the LinkedIn, Threads and Bluesky versions in the same chat, naming each network's limit from the table at the top of this page.
Check three things before you post. The hashtag count, because older advice in its training may still say 30. The length, because a caption for X or Bluesky has to fit in 280 or 300 characters. And every claim about your app, because it will fill gaps with features you do not have. More prompts are on the pages of Claude prompts for social media and ChatGPT content calendar prompts.
You can skip the copying. Connected to Spreadcast's MCP server at spreadcast.app/api/mcp, ChatGPT or Claude reads each network's limits from Spreadcast's posting rules, writes a caption per network for a post designed in your app's brand and saves it as a draft. ChatGPT social media automation shows the setup.
How Spreadcast Writes One Caption per Network: Your First Week
There is no SDK to install and no access to your developer account. Spreadcast checks your public App Store listing every day, and the caption is part of every post it makes. The full flow is on its own page.
- Step 1
Day 1: Paste Your App Store Link
Go to the start page and paste the link to your app. Spreadcast reads the name, the icon, the screenshots, the release notes and the rating. Every caption is written from those facts, so it talks about your app and not about apps in general.
- Step 2
Day 1: Read the First Post and Its Captions
The first post is drafted from the listing as a 1080 by 1350 still with typeset text, with a separate caption for Instagram, TikTok, LinkedIn, Facebook, Threads, Pinterest, Bluesky, Mastodon, Telegram and Discord, plus YouTube for video posts. Compare the Bluesky caption with the LinkedIn one to see how the same news is fitted to each. Image sizes per network are in our social media image sizes reference.
- Step 3
Day 2: Connect Your Accounts and Pick a Mode
In approve first mode the post and its captions wait for one tap from you. In full autopilot they go out at the post's slot on the content calendar. Publishing is on Pro at $29 a month and Studio at $79 a month. The free plan makes post drafts you download. See pricing.
- Step 4
The Day Your Next Version Goes Live
The daily check finds the new version. The release notes are cut down to two or three points, and the update post with its captions takes the next free slot on your calendar. You can drag it to another day. In a week with no update, Spreadcast drafts a post about one of your app's features, so the feed does not go silent.
- Step 5
The Day a 5 Star Review Arrives
A post that only shows the rating can go out by itself. A post that quotes a reviewer's words waits for your approval in both modes, because you are the one who has to ask the reviewer for permission.
What Stays With You, and the Tool to Use for It
Spreadcast writes the captions for the posts it makes about your app. These jobs sit beside that one, and each has a good tool.
Captions for Posts on Any Topic
Spreadcast is not a free standing caption box: you cannot paste a photo of your lunch or a topic and get captions back. For that, Hootsuite's free tools page lists a caption generator, an Instagram caption generator and a LinkedIn post generator, and Buffer's AI Assistant rewrites and shortens posts on Buffer's free plan.
Video Captions and Subtitles
Spreadcast designs still image posts and writes no subtitles or scripts for video. Keep a video editor for Reels and TikTok videos.
Hashtag Research
Spreadcast sets hashtags to each network's count. It has no hashtag analytics and does not learn from how earlier posts performed, so use a research tool if you track tags closely.
Replies to Comments
Comments and messages stay with you. X's automation rules require written approval from X before anyone runs an AI reply bot, which tells you how the networks see automated replies.
Google Play Listings
Spreadcast reads App Store listings today. Google Play is next on the list and not available yet. A wider look at tools that write and design posts is in the best AI social media post generators.
Caption or Subtitles? Captions for Videos on LinkedIn, TikTok, Instagram and YouTube
Caption has two meanings. On this page it is the post text. For video it also means the words shown on screen while someone speaks, which people search for as LinkedIn captions for videos or auto generated captions. Section 508's social media guidance defines closed captions as captions the viewer can turn on or off, and open captions as text that is always in the video. Here is where each network stands.
| Network | Captions on video | What to know |
|---|---|---|
| LinkedIn's help page on closed captions has you attach an SRT file in the desktop share box before posting, for a personal profile or a Page. The captions appear once the video has processed. | The LinkedIn caption limit for post text is still 3,000 characters. Section 508 notes LinkedIn also offers Add auto captions, and says to turn it off when you upload your own file so the video does not get two sets. | |
| TikTok | Auto captions transcribe your speech into on screen text, which you can edit before publishing, per TikTok's announcement of auto captions. Viewers can turn them off from the share panel. | Read the transcript before posting. App and feature names are the words speech recognition gets wrong most often. |
| Reels can carry closed captions that Instagram creates, covered in Instagram's help article on closed captions for reels. | The 2,200 character caption and the 5 hashtag cap apply to the post text, whatever the video shows. | |
| YouTube | YouTube's page on disclosing AI content lists captions among the things that need no AI disclosure, along with scripts and titles made with AI as production help. | A caption or description you drafted with ChatGPT does not need the AI label. A realistic scene that never happened does. |
Section 508 also says many platforms accept captions only as SRT files, not VTT or plain text. Spreadcast writes the post text for each network and makes no subtitle files.
Frequently Asked Questions
What is a social media caption generator?
It is a tool that writes the text that goes with a post. Most take a topic or an image and return a caption for one network. Spreadcast works differently: it writes the captions for posts it makes about your app, one caption per network, from the facts on your App Store listing.
Is there a free AI caption generator?
Yes. Hootsuite's free tools page lists caption generators for several networks, and Buffer's AI Assistant is available on its free plan. Spreadcast's free plan covers one app and makes post drafts to download, each with a small Spreadcast mark.
What is the Instagram caption character limit?
2,200 characters, according to Meta's media reference for Instagram. You do not need to use it all. Put the point in the first sentence and stop when you have said what changed and what to do next.
How many hashtags can you use on Instagram?
As of October 2026, Instagram's hashtag help page says you can use up to 5 on a post. Meta's developer reference still lists a maximum of 30, so some tools have not caught up. Stay at 5 or fewer.
How long can a LinkedIn caption be?
A LinkedIn post can contain up to 3,000 characters, per LinkedIn's help page on posts. For an app update, three short paragraphs and 3 to 5 hashtags is a good length.
Should I use the same caption on every network?
No. The limits run from 280 characters on X to 3,000 on LinkedIn, hashtags from one topic tag on Threads to 5 on Instagram, and links sit in a different place on each network. Keep the facts and the image the same and rewrite the caption to fit.
Can I use Spreadcast as a caption generator for any post?
No. It writes captions for the posts it makes for your app: updates, reviews, milestones and feature posts. It is not a general caption box, and the free tools from Hootsuite and Buffer named above are a better fit for that.
Can I quote an App Store review in a caption?
Only with the reviewer's permission. Apple's ratings and reviews guidance says customer reviews may be used in marketing materials only if the reviewer grants permission. Showing your current rating without the words is allowed.
Where These Facts Come From
Every outside number, rule and price on this page links to the page it was taken from.
- Instagram media referenceMeta for Developers
- Use hashtags on InstagramInstagram Help Center
- Add links to your Instagram profileInstagram Help Center
- How Instagram search worksInstagram
- Post and share updatesLinkedIn Help
- LinkedIn Pages best practicesLinkedIn
- Counting charactersX Developer Platform
- About X PremiumX Help Center
- How to use hashtagsX Help Center
- Automation rulesX Help Center
- Pages API posts guideMeta for Developers
- How to use hashtags on FacebookFacebook Help Center
- Content Posting API photo post referenceTikTok for Developers
- Content Posting API direct post referenceTikTok for Developers
- Getting discovered with Search: your questions answeredTikTok Creator Academy
- Adding a website link to a TikTok profileTikTok Support
- Threads posts guideMeta for Developers
- Pinterest product specsPinterest Business Help
- Creative best practicesPinterest Business
- Bluesky post schemaBluesky on GitHub
- Posts documentationBluesky
- Ratings, reviews and responsesApple Developer
- App Store marketing guidelinesApple Developer
- Instagram caption length studySocialinsider
- The state of social media engagement in 2026Buffer
- Creating accessible social media contentSection508.gov
- Free social media toolsHootsuite
- Buffer AI AssistantBuffer
- Free social media post creatorBuffer
- Generate captions for social media using generative AIAdobe Help Center
- Adobe Express pricingAdobe
- Later pricingLater
- Claude pricingAnthropic
- ChatGPT pricingOpenAI
- Instagram implements new limits on hashtag useSocial Media Today
- Add closed captions to videos on LinkedInLinkedIn Help
- Auto captions on TikTokTikTok Newsroom
- Manage closed captions for your reelsInstagram Help Center
- Disclosing use of AI contentYouTube Help
Researched and written by Spreadcast. Last checked on October 17, 2026.