For SEO specifically
- r/SEO: the large general SEO community. Good for broad questions and seeing what ranks. Heavily moderated against self-promotion.
- r/bigseo: smaller and more advanced, aimed at practitioners. Higher signal, less beginner noise.
- r/TechSEO: for technical SEO topics like crawling, indexing and site structure.
- r/juststart: focused on building and growing content sites from scratch.
For marketing more broadly
- r/marketing: a large general marketing community, useful for reach but strict on promotion.
- r/DigitalMarketing: practical digital marketing discussion.
- r/content_marketing: for content strategy and distribution.
- r/PPC: paid search and social, useful if you run ads alongside organic.
For founders and SaaS
- r/SaaS and r/startups: where software buyers and builders gather. Strong for B2B software.
- r/Entrepreneur: broad, high traffic, good for reach but noisy.
How to actually use these
Do not post the same thing across all of them. Pick the two or three closest to your buyers, learn the culture, answer questions, and mention your product only where it fits. If you would rather have this handled by people who already know these communities, a Reddit SEO agency like Upvote Labs does exactly that. For the fundamentals, start with the Reddit SEO overview.