Automated Instagram DMs run on Meta’s official API, and that API has rules. Knowing them explains what any comment-to-DM tool can and can’t do. Everything below comes from Meta’s developer documentation; the sources are at the end.
Private replies to comments
When a tool DMs someone because they commented, it’s sending what Meta calls a private reply. Two rules apply:
- One per comment. “Only one message can be sent to the commenter.” Anything more has to wait until they reply.
- Within 7 days. The private reply must be sent “within 7 days of the creation time of the comment”.
That’s why follow-to-unlock flows put the ask and the buttons in a single message, and why catch-up on old comments can’t go back more than a week.
How many per hour
Meta’s rate-limit documentation says an app “can make 750 calls per hour per Instagram professional account for private replies to comments on Instagram posts and reels”. That’s a ceiling for the API, not a target: sending at the ceiling during a spike is where accounts run into trouble.
The 24-hour messaging window
Once someone messages a business account, by replying to a story, sending a post or answering a DM, the business can reply for 24 hours. After that the window closes until they message again. Story replies, shares and mentions all arrive as messages, so replies to them have to go out within that window.
How long a message can be
| Message | Limit |
|---|---|
| Plain text | 1,000 bytes of UTF-8 |
| Text with buttons (button template) | 640 characters |
Bytes aren’t letters: an English letter is one byte, a Hindi letter three and most emoji four. Check a message with the free DM character counter.
How linkpls stays inside the limits
linkpls paces every Instagram account well below Meta’s ceilings:
- DMs: at most 200 an hour and 1,500 a day, at least 12 seconds apart.
- Public comment replies: at most 30 an hour and 150 a day, at least 45 seconds apart. Meta doesn’t publish a separate API limit for these, so linkpls sets a cautious one.
- Spikes queue up. When a post takes off, sends drain steadily instead of firing at once.
- Late sends are skipped. A reply that can no longer go out within Instagram’s windows is dropped rather than sent late.
More on how linkpls protects your account on the safety page.
