Health, home and travel decision
Wateraday
A small static calculator with a few UI and conversion functions is realistic for one technical user to build and maintain; there are no durable moats evident on the site to prevent replacement.
Visit website↗Built by Yuyu, who ships 11 products in this index
Not priced
No pricing page we fetched carried a figure, so there is nothing to compare against. The build side is still real.
$20one-off10 h to build
$0/mo1 h/mo upkeep
No published price to break even against.
No open-source build does this yet
Nothing published replaces this one, so a replacement starts from an empty file. Here is what it would have to cover.
What a replacement has to do
- Collect user demographics and activity, compute recommended water volume, convert to common units, and show actionable guidance and reminders.
What it still won’t have
- Brand polish, domain and existing SEO
- Any paid marketing or established backlinks
- Existing hosted copy and content updates
- Built-in footer list of related tools and projects
What remains hard
- Product polish and ongoing maintenance
First-year cost
No published price
Wateraday does not publish a price we could read, so there is nothing to compare against. What building costs is below.
Money you would actually spend
Time you would spend
—
What you would spend
What we assumed
The verdict above measures whether you could build it. This one is only about money.
Runnable build prompt
Build a responsive static web app (React + Vite) that calculates a user's recommended daily water intake. Core features: (1) input form for gender, age, weight (kg), height (cm), and activity level with validation; (2) hydration calculation module that outputs liters/day and number of 8oz glasses and supports unit conversion functions; (3) results page with explanatory text, dehydration signs, and tips; (4) accessible, responsive UI and basic styling (Tailwind CSS), meta tags for SEO, and a printable result; (5) CI deploy to Vercel or Netlify and optional privacy-friendly analytics (SimpleAnalytics or local logging). Out of scope: server-side user accounts, reminders/notifications, personalized historical tracking. Include error handling for invalid inputs and unit tests for calculation functions.
How we checked
How the score was reached
- Build verdict base78
- 3/3 assessment runs agreed+4
- Evidence score82
The base comes from the verdict. Everything under it is a check that either happened or did not, and each one is a fact frozen in this record rather than a judgement made at render time - so the same evidence always produces the same number.
How scoring works →Cited sources · 1
Every page the run actually retrieved.
- official productWater a Day — official product page
Integrity checks
What held up, and what did not.
