Caption

A caption is the text that appears under an Instagram post, reel or carousel. It can be up to 2,200 characters long and supports up to 30 hashtags. The caption is the primary location for Comment-to-DM call-to-actions — where businesses state the keyword that triggers an automated direct message.

What is a caption on Instagram?

A caption is the text that appears directly below an Instagram post, reel or carousel image. It supports plain text and up to 30 hashtags. Captions can be up to 2,200 characters long, although only the first 125 characters (approximately two lines) are visible without tapping "more". Everything after those first characters is hidden behind the "more" link.

Effective caption structure

Because only the first 125 characters are immediately visible, experienced Instagram marketers front-load the most important information:

  1. Hook (first 125 chars): the opening sentence should stop the scroll. A question, a bold statement, or a direct benefit. Also the right place for the Comment-to-DM call-to-action if that is the main goal of the post.
  2. Body: additional context, story or information. This is where a longer explanation goes if needed.
  3. Call-to-action: if not already in the hook, the CTA — including the keyword — goes here. Many accounts also repeat it at the end to catch people who read to the bottom.
  4. Hashtags: at the end, or in the first comment. Instagram allows up to 30; 5–10 relevant hashtags typically outperform 30 generic ones.

Caption as the Comment-to-DM call-to-action placement

For Comment-to-DM campaigns, the caption is where the keyword instruction lives. The format is simple and consistent: "Comment [KEYWORD] and I'll send you [benefit] straight to your DM."

Examples:

  • "Comment GUIDE and I'll send you the free checklist to your DM."
  • "Comment SALE for your 15% discount code — today only."
  • "Comment LIVE and we'll send you the webinar registration link."

The keyword should be all-caps so it stands out visually in both the caption and the comment section. State it in the first 125 characters of the caption if it is the primary goal of the post. For Reels, also include the keyword call-to-action as a text overlay or spoken in the video itself — repetition increases the comment rate.

Hashtags in captions

Instagram allows up to 30 hashtags per post. The general guidance is to use a mix of niche hashtags (smaller, targeted communities), industry hashtags (medium-sized, specific to your sector) and a small number of branded hashtags. Hashtags can go at the end of the caption or in the first comment — both placements have similar algorithmic effects. Avoid purely generic hashtags like #instagood with billions of posts; they offer no meaningful reach boost.

Captions and SendSeven

The caption keyword you announce in the post must match the keyword you define in SendSeven's Flow Builder condition. When someone comments the exact word (case-insensitive by default), the trigger Instagram comment received fires and the private reply goes out. The contact lands in the unified inbox alongside all other channels.