5 app ideas you can build this week

Five apps making real money in niches most people walked right past. Revenue numbers are third-party estimates.

Point your camera at any supplement bottle. Prove It scans the barcode and gives you a science-backed breakdown of whether the ingredients actually do anything. It grades each one, flags the junk, and tells you if that $40 bottle of pills is legit or marketing fluff.

The supplement industry is worth $60B+ and barely regulated. Most people have no clue if what they're taking works. And look at these economics: only ~10K downloads/mo but pulling ~$100K in revenue. That's roughly $10 per download. People happily pay because the value prop is obvious — "stop wasting money on bad supplements."

Same developer behind PayMe, which means this team has a playbook: find categories where people feel uncertainty, build the app that resolves it.

What you could build:

Screen time apps aren't new — Opal, one sec, ScreenZen all exist. But Unrot's genius is branding. Instead of shaming you with usage stats, it leans into "brainrot" — a term Gen Z already uses — and gamifies earning screen time through focus tasks, reading, or exercise.

200K downloads in 9 months. The app doesn't feel clinical or parental. It feels like it was made by people who scroll too much, for people who scroll too much. The "earn your screen time" mechanic turns restriction into a reward system, which is why it sticks.

The lesson: a crowded category with tired branding is an opportunity, not a wall. Reframe the problem in the audience's own language and you've got a new product.

What you could build:

Take any photo — your dog, your kid, a landscape — and Colorify turns it into a printable coloring page. Clean line art, multiple styles (sketch, pixel art, detailed outlines), digital coloring or print-and-go. Works for both kids and adults.

Adult coloring books were already a $3B+ market before AI. What Colorify does is make the creation personal — you're not coloring a random mandala, you're coloring your dog. That emotional hook is powerful. $200K/mo from what's essentially one AI feature wrapped in a clean UI.

This is the kind of app a solo dev could build in a weekend with an image-to-lineart API. The personalization is what makes it feel premium.

What you could build:

Military-inspired "lifestyle operating system." Daily discipline routines, cold exposure tracking, PT protocols, journaling prompts, and "mission planning" for your day. It's not for everyone — it's for men who watch Jocko Willink and David Goggins.

The numbers are wild. Only ~1,000 downloads per month, but ~$50K in revenue. That's roughly $50 per download — one of the highest LTVs you'll see in a lifestyle app. 4.96 stars with 585 reviews means near-perfect retention.

This is a masterclass in niche-down. Instead of building "yet another habit tracker," they built a habit tracker for a hyper-specific identity group that pays premium because the app reinforces their self-image. Identity > utility.

What you could build:

Daily questions, challenges, and conversation starters designed to keep couples connected. Date night ideas, check-in prompts, activities you do together. The pitch: "most relationships don't end in one moment — they drift apart."

The couples app space is heating up — Paired (193K ratings), Cozy Couples (35K ratings), Couple Joy (28K ratings) all exist. But Candle launched March 2025 and already hits ~$100K/mo. The market is growing, not saturated.

Here's the business angle that matters: every user brings exactly one other user (their partner), and both need to subscribe. That's a built-in 2x multiplier on every acquisition. Few app categories have that kind of organic viral mechanic.

What you could build:

See you next Thursday.

— Eldar