Paste your site above and run the scan. Radar reads it, works out what you built and who buys it, then checks candidate subreddits against real recent posts and real posted rules to find where your buyers already ask for what you sell. Every community it returns comes labelled by what its rules allow, and it's free, no card.
How to use it
1. Paste your URL and run the scan. Drop your homepage or landing page URL into the box above. Radar reads the page, not a form you fill in. No account, no card.
2. Radar reads your site and checks communities against it. It builds a short brief from your page (what you do, who it's for, what it can and can't do), then works through candidate subreddits and checks each one against real recent posts and the subreddit's actual rules.
3. You get a list, not a guess. Each subreddit comes back with a label: promote, soft, or hang out. Under the label sits the rule that earned it, quoted, not paraphrased. Then three days of live threads where people in that community are already asking about a problem your product solves, each with a reply drafted and ready to copy.
That's the whole loop: paste, read, post. Nobody logs into Reddit and nothing gets posted for you. You read the thread, you edit the reply if you want to, you paste it yourself under your own account.
If you'd rather browse a fixed list of communities that explicitly welcome launches before you scan anything, see subreddits to promote your startup. If you already have a subreddit in mind and want to check its rules by hand, use the subreddit rules checker.
How the scan finds communities
The scan starts by reading your site, not by asking you to describe your product. It pulls a product brief out of the page: name, category, who it's for, what it does, and what it doesn't do. That brief is what everything downstream gets checked against.
From there it goes looking for candidate subreddits four ways. It runs web searches for your category and the words people use to describe your kind of problem. It searches Reddit directly by topic. It reads articles and lists that already round up subreddits for your niche, the "best subreddits for X" posts that show up in search. And it checks a fixed list of launch venues, the communities that explicitly exist for people showing off what they built, alongside whatever niche communities came up in the first three steps.
That gives a pile of candidates, most of which are wrong. The next step is verification, and this is the part a plain list can't do. For each live subreddit, Radar pulls the community's actual posted rules from Reddit (or its sidebar description when there are no formal rules), along with up to 30 real post titles from the last two weeks. One model call reads your product brief against that evidence and returns two things: a fit label and a promo policy. Nothing is assumed. A subreddit with no rules and no sidebar doesn't default to "sure, go ahead," it comes back unknown, because missing evidence never establishes permission.
That's the difference between this and a subreddit name generator. A name generator matches keywords. This checks whether the people posting there this month have the problem you solve, and whether the mods will let you say anything about it.
Radar has been auditing subreddits this way since early September 2026, and the pattern holds up across almost a thousand communities checked so far: where the rules say something about self-promotion, roughly half ban it outright, another third allow it only under specific conditions, and the rest allow it plainly. Assuming a subreddit is open just because you haven't been told otherwise is the single most common way founders end up banned. Missing evidence isn't permission, it's a reason to hold back.
Why the label is decided by who the members are
The fit label isn't about topic overlap. It's about whether the people in that room are your buyers. A subreddit can share your keyword and still be the wrong room: a library for developers isn't a no-code tool's audience, an iPhone app has no business pitching r/Android, and a community built entirely from your product's actual buyers is never a fit to skip, even if it looks niche.
Radar checks this by reading your product brief's audience and capabilities against what the subreddit's own posts show people doing there. That's why the labels aren't a single yes/no. There are four:
- Promote: the rules allow a disclosed founder to present the product, and members are asking for tools like it, or it's a launch venue built for exactly this.
- Soft: members are discussing the problem itself, and a helpful answer may mention the product once, with disclosure.
- Hang out: you belong in the room and can be useful, but you must never name the product.
- Skip: this isn't your audience, full stop.
Separately, Radar reads the rules alone for a promo policy: allowed, restricted (conditions beyond disclosure, like a specific flair, a participation ratio, mod approval, or a designated day), banned (promotion is prohibited outright or confined to one designated thread), or unknown (no rules and no sidebar to go on).
The two combine with a cap. A subreddit can be a strong audience fit and still get capped down: a "promote" fit paired with a "banned" policy comes back as "soft" or "hang out" instead, because the fit says these are your people but the policy says you can't pitch to them directly. Fit tells you who's in the room. Policy tells you what you're allowed to say. The label you see is both, together.
"Restricted" is where most of the nuance lives, and it's rarely a single blanket rule. Across the restricted verdicts Radar has logged, the condition attached is usually one of four things: promotion confined to one designated thread or day, a participation ratio (post nine helpful comments for every one that mentions your product, that kind of math), a required flair marking you as the founder, or a rule that you ask a mod first and wait for a yes. None of those are "no." They're all "yes, but only like this," and the scan surfaces which one applies instead of leaving you to find out by trial and error.
Why post titles beat the subreddit's name
The name of a subreddit is marketing copy written by whoever created it years ago. It's not evidence of what happens there now. That's why Radar reads up to 30 recent post titles per subreddit before assigning a label, not just the description.
r/marketing is the clean example. The name says "people who care about marketing," which sounds exactly like your audience if you sell a marketing tool. Read the actual rules and it's the opposite: self-promotion and shilling are against the rules there, full stop. A subreddit with your exact keyword in the name can still be a place where mentioning your product gets the post removed and possibly you banned.
The flip side shows up just as often: a subreddit that looks locked down on the surface turns out to have a specific, workable path. r/indiehackers doesn't ban self-promotion, it channels it, allowed once per post with a SHOW IH flair, tied to asking for feedback rather than just announcing. r/nocode is similar, a value-add post, a company flair, disclosure, or the monthly launch thread. Reading only the subreddit's name or its general reputation ("that one's strict") misses the actual mechanism you're allowed to use.
Small and slow communities get the same treatment, and they default to "hang out" more often than large active ones. If a subreddit has a handful of posts a week and no clear pattern of people asking for tools, there isn't enough recent evidence to say the rules and the audience line up for a pitch, so the label errs toward showing up and being useful rather than assuming you're welcome to sell.
To see this rule-reading step in isolation, on a subreddit you already have in mind, the subreddit rules checker does exactly that on its own, and the reply quality checker tells you whether a specific draft would survive that subreddit's rules before you post it.
Doing it by hand instead
You don't need a tool to do any of this. It just takes longer, and it's easy to skip a step under a deadline.
Start with Reddit's own search and search for the problem, not your product category. Someone looking for what you built rarely searches your category name, they search the pain: "how do I track X," "is there a tool for Y." Search those phrases directly in Reddit's search bar and see which subreddits keep surfacing.
Once you've found one good subreddit, check its sidebar for related communities. Most active subreddits list a handful of neighbors, and mods of adjacent communities often overlap, so a related list is a decent shortcut to more candidates.
Then read the rules on every candidate, in full, not just the ones about self-promotion. Rules 2 and 7 might ban shilling while rule 4 sets a totally separate condition on flair or posting day that only shows up if you keep reading. Skimming the first rule and stopping is how a permanent ban happens.
Keep a short list, not a long one. Ten subreddits you've verified beat fifty you've assumed about. Write down the label you'd give each one and the rule you're basing it on, so you can check back before you post rather than relying on memory from three weeks ago. If a subreddit runs a weekly or monthly thread for exactly this kind of post, bookmark it directly, a rule that confines promotion to one recurring thread is the single most common restriction you'll run into, and it's easy to miss if you only skim the top-pinned rule.
This works. People who launched before any of these tools existed did exactly this and found good communities. It costs time, and rules change, so a list from six months ago needs a second pass before you trust it again. I did this by hand for a while, badly. I got a 28-day ban from a subreddit and later a permanent one from another, for replies I thought were helpful that still broke a rule I hadn't read closely enough. That's a fair chunk of why this scan exists.
What to do with the list
Once you have labelled subreddits, treat the label as the instruction, not a suggestion.
Hang out subreddits: help without naming the product. Answer the question, be useful, build a small reputation. The product never comes up here, not in the reply, not in your bio for that thread, nowhere.
Soft subreddits let you disclose one mention. Answer the actual question first, and if the product fits, mention it once, in the final third of the reply, and say plainly that you built it. No link unless the community allows it.
Promote subreddits are where you can make an actual launch post or a direct pitch in a thread asking for exactly this. Still disclose, still lead with substance.
Across all of it: one pitch per subreddit, then a cooldown before you try that subreddit again. Mentioning your product in every thread you touch in the same community reads as spam even where the rules technically allow it, and mods notice the pattern faster than they notice any single post. Space it out. In practice, when Radar drafts a reply, roughly half the time the honest answer is a helpful reply with no pitch at all, because that thread isn't the moment for one. That ratio is closer to how this should feel than the alternative.
And before you paste anything anywhere: read the whole thread first, not just the post. Check the top comments. If someone already gave the exact answer you were about to give, don't repeat it, add something they missed or skip that thread entirely.
Before you commit to a schedule of pitches, it's worth seeing what one is worth in hours and revenue. The Reddit marketing ROI calculator runs the arithmetic on your own numbers. And for the reasoning behind which threads are worth replying to at all, how Radar decides a thread is worth a reply walks through the scoring in full.
What the scan will not do
The scan reads. It doesn't act.
It never posts anything, to any subreddit, at any point. It never logs into Reddit, so there's no account of yours it could touch even if it wanted to. It doesn't use Reddit's official API at all, it reads through a licensed commercial data provider instead. There are no reply quotas to hit and nothing gets auto-posted on a schedule or a trigger. Every reply the scan shows you is a draft sitting on the screen, waiting for you to read it, edit it if you want to, and paste it yourself, under your own username, in your own browser.
It reads through a licensed commercial data provider rather than Reddit's official API, which is also how it can search across threads and subreddits you haven't already found on your own; the approach is covered in more detail in find Reddit threads without the Reddit API.
If you want the full loop, not just the free scan, Scan my site free walks through it on the landing page: the same read-your-site step, then the inbox of live threads that refreshes as new ones come up.
FAQ
Does this tool post to Reddit for me?
No. It never logs into Reddit and never posts anything. It reads your site, finds and labels communities, and finds live threads with a reply drafted for you to copy. You paste it yourself, in your own browser, under your own account.
How is this different from a list of subreddits for my niche?
A list matches keywords to a category. This scan reads your actual site to build a product brief, then checks each candidate subreddit's real recent posts and real posted rules against that brief before labelling it. A subreddit can share your keyword and still get labelled "skip" if the people posting there aren't your buyers, or "hang out" if they are but the rules ban pitching.
What do the promote, soft, and hang out labels mean?
Promote means the rules allow a disclosed founder to present the product and members are asking for tools like it. Soft means members discuss the problem and a helpful answer can mention the product once, with disclosure. Hang out means you belong in the conversation but should never name the product. A strong audience fit still gets capped down to soft or hang out if the subreddit's rules ban promotion outright.
Does it use the Reddit API?
No. Radar doesn't log into Reddit and doesn't call Reddit's official API. It reads subreddit rules, post titles, and threads through a licensed commercial data provider.
Is there a limit on how many times I can run this?
The tool is free with no card required. It hands your URL to Radar's real scan on the landing page, the same free scan described above.
What if my product doesn't fit any of the labelled communities well?
That's a real, useful answer, not a failure of the scan. If a subreddit's audience doesn't match your product, or the rules ban promotion outright with no soft path, the scan will say skip or hang out rather than force a promote label that would get you banned. Reading that beats posting into the wrong room and finding out from a mod.
Can I check one subreddit's rules without running the full scan?
Yes. The subreddit rules checker does that one step on its own, for a single subreddit you already have in mind, with the promo verdict and the rule behind it.