CheapMap

Just launched CheapMap (https://cheapmap.app) — a free, community-driven map that surfaces affordable restaurants, street-food stalls, gas stations, and shops in Vietnam priced under VND 100k (~$4).

• Why I built it?

Existing VN food/location apps (Foody, Riviu, Lozi) lean toward mid- and high-end venues. Most top listings are paid placements. The VND 20–50k street-food spots locals actually go to barely show up, or get buried 10 sponsored results deep.

I'm Vietnamese, I live here, and I find these places by asking friends or scrolling Facebook groups. There was no map for them. So I made one.

• Status after 22 days live

- 43,000+ ACTIVE locations across 8 countries (VN-first)

- ~50 organic users/day, zero paid acquisition

- $0 revenue, testing affiliate model via deal aggregator

• What I think makes it different

- Community-weighted ranking (Bayesian score from votes + reviews + breadth of unique contributors). Business owners can't pay to rank.

- Anomaly detection every 2 hours catches vote rings + burst behavior; downweights matching votes to 10%.

- Open contribution — guests submit prices/votes/reviews without signup. Rate-limited per IP + cookie.

- Bilingual VI/EN, no tracking, no signup wall.

• Tech (for the curious)

Spring Boot 3.2 + Java 21 virtual threads + Next.js 14 App Router + PostgreSQL/PostGIS on Supabase + Cloudflare R2 + Vercel + Railway. ~$20/mo all-in for 43k location pages + 360 city×category SEO cells + Tools Hub (~205 pages).

• Feedback I'd love

1. Does "community-weighted ranking" register as different from Yelp/TripAdvisor on first visit, or just look like another review site?

2. Mobile UX on the map — brutal honesty welcome.

3. Anyone who's grown a hyperlocal product past day 30 — what actually mattered? SEO is currently top-3 priority but I'm open to being told it's the wrong call.