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валерій повзун
валерій повзун

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I analyzed what people complain about online - then built the fix in a single HTML file

#javascript #showdev #sideprojects #webdev

The research

I went through complaint analyses aggregating thousands of posts from Reddit, X and dev communities. One pain point kept showing up outside the dev bubble:

  • 64.8% of people forget to cancel a free trial before getting billed
  • the average US household spends ~$273/month on subscriptions while estimating ~$111 — roughly $3,200/year quietly disappearing
  • 89% of consumers underestimate their total subscription spend

The punchline: the most popular "solutions" are subscription-tracking apps that themselves require a subscription — and want read access to your bank account.

The constraints

People's actual complaints translate into a spec:

  1. No subscription for a subscription tracker. Free, no paywalled "basic" features.
  2. No bank linking. Manual entry is fine — people have 5-15 subscriptions, not 500.
  3. No account. No email, no password, no onboarding.
  4. Privacy by architecture. If there's no server, there's nothing to leak.

That spec has a natural shape: a single static HTML file with localStorage.

What it does

SubTracker (~34 KB, zero dependencies):

  • monthly / yearly / per-day spend, multi-currency with user-editable rates
  • per-cycle normalization (weekly/monthly/quarterly/yearly → monthly cost)
  • trial flag → prominent "cancel before X or you'll be charged" banner
  • usage rating per subscription → "you could save N/year" from the ones you barely use
  • upcoming charges (30-day window) with countdown, auto-rolling billing dates
  • category breakdown chart, search/filter/sort, JSON export/import, dark/light theme

No framework, no build step. Date math for billing cycles, CSS variables for theming, a 10-color hash palette for service avatars.

Try it

Live: https://valera99686.github.io/subtracker/ — click "Показати приклад" (Show example) for demo data.

The interesting lesson for me: the gap between "what people complain about" and "what gets built" is often just packaging. Nobody needs another VC-funded fintech app for this — they need a file that opens in a browser and tells the truth about their spending.

What would you add?

Update (June 12): added income tracking. Enter your salary or freelance income and SubTracker shows how much is left after subscriptions and what percentage of your income they eat.

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