Reddit does not organize around people. It organizes around topics, which is why the follower-count instinct from every other platform gives you nothing here. Nobody is going to follow your brand. What matters is whether the rooms where your buyers argue about tooling are rooms you can usefully be in.
Finding those rooms takes about an afternoon. Most of that afternoon is reading, not searching.
Start from search results, not from subreddit lists
The common approach is to look up “best subreddits for B2B SaaS” and monitor whatever comes back. This gives everyone the same four communities, all of them enormous, general, and saturated with other founders doing exactly the same thing.
Work backwards from real queries instead.
Take the five phrases a buyer would type when they have your problem and have not heard of you. Not your category name. The problem in their words. Something closer to “how do you handle X without paying for Y” than “customer intent platform.”
Search each one on Google with site:reddit.com appended. Write down which subreddit each result came from.
The list you end up with is empirical. It reflects where Google thinks these discussions happen, which is a useful proxy for where they get read, and it will contain communities you would never have guessed. This step alone tends to surface two or three high-value niches that no listicle mentions.
Two kinds of community, two different jobs
The big general business communities are worth understanding but rarely worth prioritizing. They have huge membership and broad discussion. They are also where every founder goes first, which means the promotion tolerance is low, the moderation is tired, and the threads asking for tool recommendations are already ten comments deep by the time you see them.
Use them for reading the market and understanding how people describe their problems. Do not build your channel on them.
The role and stack specific communities are where the money is. Smaller, quieter, and full of people describing their actual daily workflow. Someone in a technology-specific subreddit asking how the community handles a task is describing a purchase they are considering, in detail, unprompted. That thread is worth more than fifty upvotes in a general startup subreddit.
The tradeoff is that these communities notice outsiders instantly. You cannot parachute in.
Judging whether a subreddit deserves your time
Membership count is close to meaningless. Four checks matter more.
Read the sidebar and the rules, all of them, before anything else. Some communities ban self-promotion outright. Some allow it with disclosure. Some allow it only in a weekly thread. Knowing this before you comment is the difference between a channel and a ban.
Look at what happens in the comments, not at the upvote counts. A subreddit where posts get many upvotes and few comments is a place people scroll. A subreddit where a modest post attracts thirty thoughtful replies is a place people talk, and talking is what you need.
Search the subreddit itself for phrases like “what do you use for” or “recommend a”. If those threads exist and get real answers, the community treats tool discussion as normal. If they do not, the community will treat your tool discussion as an intrusion no matter how well you write it.
Check whether recommendations survive. Find a thread where someone named a commercial product and see what happened. Did it get upvoted, argued with, or removed? That tells you the actual rule, which is often different from the written one.
Do not skip the lurking
This is the step everyone skips and it is the one that determines whether any of the rest works.
Spend two weeks in your chosen communities without mentioning anything you sell. Comment on things you know about. Answer questions where your answer has nothing to do with your product. Get a feel for the tone, which is usually more blunt and less polished than marketers expect.
You are doing two things. You are building an account with history, which is what stops a moderator from removing your first useful comment as drive-by promotion. And you are learning the vocabulary, because the phrase your market uses is almost never the phrase on your homepage, and that gap is why keyword lists built from marketing copy catch nothing.
Keep a note of the exact wording people use for the problem. That note becomes your keyword list.
Turning the list into something you can run
Somewhere around five communities and a dozen phrases, checking manually every morning stops being sustainable. Not because it is hard, but because it competes with everything else and loses.
The threads you want are also time-sensitive. Comments posted early accumulate the visibility that keeps them near the top, and a reply added two days later sits where nobody scrolls. Finding the right thread late is barely better than not finding it.
That is the point where monitoring earns its cost. MarkGroww watches the communities you pick, scores each new thread against what you actually sell so the job postings and news mentions do not reach you, and drafts a reply for the ones that clear your bar. A human still edits and posts every one, which is deliberate. Automated posting is the fastest route to a ban.
Whatever you use, the requirement is the same: you hear about the good threads in minutes, and the alerts stay clean enough that you keep opening them.
Common questions
How many subreddits should I monitor?
Five to fifteen. Fewer than five and you will not see enough volume to learn anything. More than fifteen and the alert channel becomes something you mute.
What if the subreddit bans links?
Answer the question in plain text and name your product without linking. Anyone interested will search the name. This often performs better than linking, because a text mention reads as a recommendation while a link reads as an ad, and automod rules usually key on links.
My market is not on Reddit. Now what?
Check before believing it. Very few technical or business audiences are genuinely absent, though they are often in a subreddit named after a tool or a job title rather than an industry. If your buyers really are elsewhere, the same method transfers. Hacker News works well for developer-facing products.
How long before this produces anything?
Expect a few weeks before the first genuinely qualified conversation, because it depends on someone asking the right question rather than on you shipping anything. The lurking period is not wasted time, it is the thing that makes the later comments land.
Want the shortcut? Scan your site free and we will tell you which communities and threads already discuss your category. Thirty seconds, no card, no sign-up.