Answers
The rules, straight from the platforms.
Short answers to what creators ask most, each with a link to the platform's own documentation. Checked regularly, because the rules keep changing.
DMs and comments
- Is comment-to-DM allowed on Instagram?Yes. Meta lets apps send one private message to each person who comments on a post or Reel, within 7 days of the comment. It's the official "private replies" feature, not a workaround.
- How long can you DM someone after they comment on Instagram?7 days. Through Meta's private replies, an app can send one message to a commenter within 7 days of their comment on a post or Reel. After that, you can only message people who write to you.
- Can you automate Instagram DMs?Partly. Apps can answer people who message you, and send one private reply to people who comment, but they can't message anyone first. Cold DMs to strangers aren't possible through Instagram's API.
- Can a business message someone first on Instagram?Not through an app. Instagram's API only lets a business reply to people who wrote first, commented, or mentioned it in a story. You can still start a chat by hand from the Instagram app.
- What is the Instagram 24-hour messaging window?When someone messages your business account, apps can reply for 24 hours after their last message. Each new message from them restarts the 24 hours. Outside it, automated messages can't be sent.
- What's the difference between a private reply and a DM?A private reply is a DM sent because someone commented. It looks like any other message, but the rules differ: one message per comment, within 7 days, and you can't continue unless the person answers.
- Can you auto-DM from a TikTok comment?No, not through apps. TikTok's messaging API lets business accounts answer messages people send them, but there's no official way for an app to start a DM from a comment. Reply publicly with the link, or point people to your bio.
- Can you automate TikTok DMs in the EU?Officially not yet. TikTok's docs say its Business Messaging API isn't available for accounts registered in the EEA, Switzerland or the UK, and ManyChat says the same. Some EU users report that connecting works, so test before you rely on it.
- Does ManyChat work on TikTok in Europe?Officially no. ManyChat's help center says users in the EU and UK can't connect TikTok yet, because TikTok's messaging API isn't available there. ManyChat runs a waitlist, with no date.
- Which platforms does ManyChat support?Five: Instagram, TikTok, WhatsApp, Facebook Messenger and Telegram. They're the platforms with a messaging API. YouTube, Threads, X and Bluesky aren't on the list, and ManyChat doesn't schedule posts.
- Does YouTube have DMs?No. YouTube removed its built-in messages in September 2019. To reach viewers, reply to comments, pin one with your link, or post in the Community tab.
- Can you auto-reply to YouTube comments?Yes, through YouTube's API, but within a quota. Each reply costs 50 of the 10,000 units an app gets a day by default, so about 200 replies per app a day unless Google raises it.
- Does the Threads API support DMs?No. Threads has DMs in the app since July 2025, but the API has no messaging: apps can post, reply to comments and read insights, not send or read DMs.
- Can you send Bluesky DMs with an API?Yes. Bluesky's chat API lets apps send and read DMs, if the account owner grants message access. Whether a message arrives depends on the recipient's settings, which can limit DMs to people they follow.
- Is cold DMing allowed on X?Sending a DM by hand is fine. Automated cold DMs aren't: X's rules ban spam and unsolicited automated messages. Automated replies to people who messaged you first are allowed.
- How much does the X API charge per DM?X's API is pay-per-use. Third-party trackers put sending a DM at about 1.5 cents and reading one at about 1 cent. Check X's developer console for your exact rate.
- What should a comment-to-DM message say?Deliver what you promised in the first line, with the link, then ask one easy question. Instagram and Facebook allow only one message unless the person answers, so the first one has to work on its own.
Video limits
- How long can an Instagram Reel be?Up to 3 minutes in the Instagram app (since January 2025). Through the API that scheduling apps use, Reels can be 3 seconds to 15 minutes, up to 300MB.
- How long can YouTube Shorts be?Up to 3 minutes, as long as the video is square or vertical. Videos uploaded since October 15, 2024 that meet both are Shorts; anything longer or landscape becomes a regular video.
- What are TikTok's video requirements?Through apps: MP4, MOV or WebM, up to 4GB, 23 to 60 fps, each side between 360 and 4,096 pixels, and up to 10 minutes. Most accounts can post 3 minutes through apps; some get 5 or 10.
- How long can a Facebook Reel be?3 to 90 seconds when it's posted through Meta's API, at 9:16 and at least 540 × 960 pixels. Longer or landscape videos can still go up as a regular Page video.
- How long can a Threads video be?Up to 5 minutes and 1GB, as MP4 or MOV. Threads accepts almost any shape, from 0.01:1 to 10:1, though 9:16 avoids cropping.
- How long can a video on X be?Through X's API: up to 20 minutes and 8GB for standard accounts, and up to 125 minutes and 16GB with Premium. The shape must be between 1:3 and 3:1.
- What's the video limit on Bluesky?3 minutes and 100MB per video, since March 2025 (it was 1 minute before). One video per post, and it can't be combined with images.
Captions and hashtags
- How many hashtags can you use on Instagram?Five. Instagram limited posts and Reels to five hashtags in December 2025, down from 30, saying a few specific hashtags work better than many generic ones.
- How many characters can an Instagram caption have?2,200 characters, including spaces, emoji and hashtags. Only about the first 125 show before "more", so the first line has to work on its own.
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