How do I track which post a comment-to-DM lead came from?

Use a different keyword on every post and never reuse one, so the comment tells you the post. Then remember Instagram only allows one private reply within seven days of a comment, so leads from older posts, or people who DM the keyword instead of commenting, need to be linked by hand.

Comment-to-DM ("comment GUIDE and we'll send it to you") is one of the cleanest ways to attribute Instagram leads, because the comment sits on a specific post. It breaks down in three predictable ways:

• Reused keywords. If three posts all say "comment LINK", you can't tell which one drove the comment.
• People skip the comment. Some will DM the keyword directly, and that DM has no post attached.
• The seven-day window. Meta's private reply rules allow one message within seven days of the comment, and follow-ups only after the person replies. After a week, the automation can't respond.

Keep a simple keyword register per client (keyword, post, date) and treat anything outside those rules as a lead to link by hand.

The full method is in How to Tell Which Instagram Post a DM Came From (What Meta Tells You, and What It Doesn’t).