8 Places to Find Your Next App Idea (Reddit & Beyond)
Short answer
Quick answer: The best app ideas aren't invented, they're found in complaint threads, one-star reviews, and wishlists other people have already written for you. Reddit (specific communities like r/SomebodyMakeThis, r/SideProject, and r/vibecoding, not just browsing the front page) is the richest single source, but Y Combinator's own published Request for Startups, Indie Hackers build-logs, Hacker News "Ask HN" threads, Product Hunt comment sections, app store one-star reviews, and G2/Capterra feature-gap complaints all surface the same thing: a specific person, publicly, saying what they wish existed.
Vibe coding removed the excuse that used to kill most side-project ideas - "I don't have a dev team to build it." Once you can go from a plain-language prompt to a working, deployed app, the bottleneck moves from can I build this to is this worth building. That shift makes idea-sourcing a real skill again, and the good news is you don't have to guess: there are specific places online where people say, in public, exactly what tool they wish existed. Below are eight of them, roughly ordered from richest signal to most work required to extract it.
1. Reddit — but specific communities, not the front page
Reddit is the obvious answer, and it's obvious for a reason: it's the largest concentration of people publicly complaining about problems and asking "does something like this exist?" anywhere online. The trick is knowing which communities actually produce buildable ideas rather than just general startup chatter. Communities regularly cited by builders for this specifically include r/SomebodyMakeThis (built entirely around "somebody should make this" requests), r/SideProject, r/IMadeThis, r/micro_saas, and r/vibecoding — the last of which has grown specifically around people building and sharing AI-built apps, which makes it a direct source of validated "here's what I wish this did" feedback on real, shipped tools.
Browsing isn't the same as mining, though. One builder whoscraped Reddit, Hacker News, and Product Hunt daily for months to find startup ideas ended up scoring every problem they found across three simple dimensions: demand (are people actively complaining or offering to pay?), market gap (is there no clean existing solution?), and build effort (could one person realistically build it in a weekend?). That three-part filter is worth stealing even if you never automate it — it's the difference between "someone online mentioned wanting X" and an idea you can actually act on. There's also a dedicated curated site,SomebodyMakeThis, that pulls exactly this kind of Reddit-sourced idea into one browsable list if you want a head start.
Best for: the widest raw volume of unfiltered problem statements, if you're willing to apply a filter yourself.
2. Y Combinator's Request for Startups (RFS)
Y Combinator publishes a seasonal, named list of specific problems it wants founders to build companies around — and unlike a forum thread, it comes with YC's own reasoning for why each category matters right now. The Fall 2026 RFS list includes 13 named categories, among them AI-powered adaptive tutoring for young learners, infrastructure specifically for deploying small-scale purpose-built tools ("a cloud for small software"), voice interfaces and monitoring systems for an aging population, and self-maintaining APIs — agents that automatically update a codebase when a third-party API changes. You don't need to be raising venture funding to use this list; it's a free, expert-curated signal of where informed people think there's unmet demand, and several categories (small, purpose-built tools; consumer AI products; compliance automation) are realistic solo-builder scope, not just funded-startup scope.
Best for: ideas backed by someone else's market research, refreshed on a predictable schedule.
3. Indie Hackers
Indie Hackers is where solo builders post their actual build logs, revenue numbers, and — most usefully for idea-mining — the specific problem that made them start building in the first place. Reading "why I built this" posts surfaces the underlying pain point separately from the finished product, which means you can spot the same unmet need showing up in a slightly different form and go build your own version, or a better one.
Best for: understanding why an idea worked, not just that it did — useful for spotting adjacent, still-unbuilt variations.
Build this with a prompt on Greta.sh — describe the app, Greta writes and deploys it.4. Hacker News "Ask HN" threads
Periodic "Ask HN: What tool do you wish existed?" and similar threads on Hacker News pull a different crowd than Reddit — more technical, more B2B-leaning, often earlier in noticing a gap before it's obvious elsewhere. The audience skews toward engineers and technical founders, so ideas surfaced here tend to be developer tools, infrastructure, or workflow problems rather than consumer apps — a useful complement to Reddit's broader, more consumer-leaning complaint volume.
Best for: developer-tool and infrastructure gaps, spotted early by a technical audience.
5. Product Hunt comment sections
The comments under a new product launch on Product Hunt are an underused source: people routinely show up to say "this is close but I wish it also did X" or "I use [competitor] but hate that it doesn't Y." That's a validated complaint about a product that already has paying or signed-up users — meaning the market itself is proven, and the comment is telling you exactly what's missing from it.
Best for: finding the specific missing feature in an already-validated category, rather than validating a brand-new category from scratch.
6. App Store and Google Play one- and two-star reviews
Negative reviews on an existing, popular app are some of the most specific, unfiltered product feedback available anywhere — people write them in the exact moment of frustration, with no incentive to be diplomatic. Pick a category you understand well, read the lowest-rated reviews of the top few apps in it, and look for the same complaint repeating across multiple reviews and multiple competing apps. A complaint that shows up everywhere in a category is a much stronger signal than one person's one-off gripe.
Best for: finding a specific, recurring failure mode in an already-large, already-proven market category.
7. G2 and Capterra reviews (the "feature-gap method")
For B2B and SaaS ideas specifically, G2 and Capterra reviews serve the same purpose as app-store reviews but for software companies actually pay for — which means the willingness-to-pay is already established. The technique specifically called the feature-gap method involves reading reviews of category-leading tools for the recurring "I wish it also had" or "we ended up building our own workaround for..." comments, which point directly at either a feature a competitor could ship or a standalone tool built to fill exactly that gap.
Best for: B2B software ideas where the buyer's willingness to pay is already proven by the existing market.
8. Your own workplace's internal complaints
The least glamorous source is often the best: the spreadsheet-turned-nightmare, the Slack channel used as a substitute for a real tool, the process everyone on your team complains about but nobody's fixed. You already have the deepest possible context on this problem — you don't need to interview anyone or validate demand, because you and your coworkers are the validated demand. It's also the fastest to test, since you have built-in first users the moment it works.
Best for: ideas with instantly available first users and zero cold-market validation risk — but a smaller total addressable market unless the problem turns out to be common beyond your own workplace.
Comparison table
| Source | Signal type | Audience | Effort to mine | Best for |
|---|---|---|---|---|
| Reddit (specific subs) | Direct requests, complaints | Broad, consumer-leaning | Medium — needs filtering | Widest raw volume |
| YC Request for Startups | Curated, expert-vetted categories | Founders, investors | Low — pre-filtered | Big-picture direction |
| Indie Hackers | Build-log context, "why I built this" | Solo builders | Medium | Understanding root cause of demand |
| Hacker News (Ask HN) | Early, technical gaps | Developers, technical founders | Medium | Dev tools, infrastructure |
| Product Hunt comments | Missing-feature requests | Early adopters | Low | Gaps in already-validated products |
| App Store / Play reviews | Recurring frustration | Consumers | Medium | Consumer app category gaps |
| G2 / Capterra reviews | Feature gaps, paid workarounds | B2B buyers | Medium-high | Proven-demand B2B ideas |
| Your own workplace | Firsthand pain | You and your team | Low | Fastest path to real first users |
From idea to shipped app
The three-part filter before you build
- Real demandRepeated complaints, or people actively offering to pay for a fix — not one frustrated thread.
- A genuine market gapNo clean existing solution. Check the incumbents before assuming the space is open.
- Fast enough to testBuildable while the momentum lasts, so you validate with a working app rather than a spreadsheet.
Finding the idea is only step one — the actual advantage of vibe coding is collapsing the distance between "someone online wishes this existed" and a working, deployed version of it. The fastest way to test whether a Reddit complaint or a one-star review is a real opportunity is to describe it to an AI app builder likegreta.sh and see a working, deployed version the same day — rather than spending weeks validating on paper before you've built anything a real user could react to. Once you've got a candidate idea from any of the eight sources above, our guide onPRD templates for AI app builders is the natural next step for turning a rough idea into something an AI builder can execute precisely, anda practical checklist for scalable vibe-coding projects is worth reading before you build past a weekend prototype. If the idea you found is aimed at a nonprofit or community use case rather than a paid product, we covered that specific angle separately in10 No-Code App Ideas for Nonprofits and Community Organizers, and if you're weighing which AI coding tool to actually build with once you've settled on an idea, see8 AI Coding Agents, Ranked After the Same Build Test. For lower-stakes practice ideas while you build up the muscle of shipping fast,12 Fun AI Projects That Also Improve Your Coding Skills is a good companion list.
Once you've picked a candidate idea,go build the first version on greta.sh — describe the problem you found in plain language and get a live, deployable app instead of another validation spreadsheet.
Frequently Asked Questions
Is Reddit really the best single source for app ideas?
It's the highest-volume source, which isn't quite the same thing as "best." The trade-off is that Reddit's signal needs filtering — most complaint threads are venting, not validated demand — while sources like Product Hunt comments or G2 reviews come with the market's willingness-to-pay already partly proven. Reddit is the place to cast the widest net; the other seven are where you narrow it.
How do I know if an idea I found is actually worth building?
Borrow the three-part filter mentioned above: is there real demand (repeated complaints or people actively offering to pay), is there a genuine market gap (no clean existing solution), and is it feasible to build fast enough to test it before you lose momentum. An idea that's strong on demand but has five well-funded competitors already solving it cleanly is a weaker bet than a smaller, underserved gap.
Should I build the exact thing people asked for, or my own take on it?
Usually your own take. A single Reddit comment or app review tells you a problem exists, not the ideal solution to it — that's still your job to design. Treat these sources as proof a problem is real, not as a finished spec.
Do I need to validate an idea before building it if I'm using an AI app builder anyway?
Validation still matters, but the cost of being wrong drops significantly. When building a prototype takes a prompt and a few hours instead of months of engineering time, the smarter move for a promising-but-unproven idea is often to build a minimal version and put it in front of real users rather than fully validating on paper first.
Is it ethical to build an app based on an idea someone else posted publicly?
Public requests for a tool to exist are exactly that — public, and often explicitly an invitation ("somebody make this"). Where it gets murkier is copying a specific existing product's design or branding rather than building your own solution to the same underlying problem; solving the same problem differently is normal competition, not a copy.
