How Do You Build Trust on Reddit Without Sounding Promotional?

The best way is to be helpful and stay on topic. Give a clear answer when you have something useful to share and keep your replies natural. Don't post just to add another reply.

One of the best ways that I've seen people discuss is having a 10-1 ratio of real posts to promotional posts. Effectively you post 10 actual posts or comments that can be helpful, and just general information that doesn't mention any product. For every 10 of those you do, do one post that is promotional, following that subreddits rules of course.

What helped me most: be useful in threads where your product can't be mentioned at all. If your history is full of genuinely helpful answers on unrelated questions, the one time you mention what you work on reads as a person, not a campaign. Also answer the question fully in the comment itself. When the comment already solves the problem, nobody minds a short note at the end that you built something for it. When the comment only works if they click, it reads like an ad.