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Bills that explode

Usage-based services charge for every request, token and function run, whether a customer, a bot or a bug caused it. This trail covers eight ways AI-built apps run up surprise bills: open AI endpoints, crawler traffic, free-credit farming, self-triggering functions, runaway browser requests, SMS pumping, oversized images and paid APIs called too often, and how to put a ceiling on each.

Scenarios
8
Total time
34 minutes
Free to try
The first one

8 scenarios on this trail

  1. Next up · Free · 4 minThe open summarise buttonYour app has a free 'summarise this PDF' button. Your AI bill says you made 2 million requests last night. You have 60 users.
  2. Stop 2 · Pro · 4 minA quiet week, a loud billAlmost nobody visited your site this week. Your hosting bill is forty times higher than usual.
  3. Stop 3 · Pro · 4 min500 signups overnightYou give every new account 50 free AI credits. You wake up to 500 new signups and no new customers.
  4. Stop 4 · Pro · 4 minThe update that updates itselfYou added a function that stamps 'updated_at' whenever a profile changes. By morning your database bill has a new digit.
  5. Stop 5 · Pro · 4 min2 million requests from one tabYou left your dashboard open overnight. Your database usage page shows 2 million requests from a single browser.
  6. Stop 6 · Pro · 4 minThe 40,000 SMS codesYour phone sign-in sends a code by SMS. Overnight it sent 40,000 codes to numbers in countries you do not serve.
  7. Stop 7 · Pro · 5 minThe 4 MB thumbnailYour marketplace shows 24 small product photos per page. On phones it takes ages to load, and your storage bill warns you are over your data transfer limit.
  8. Stop 8 · Pro · 5 minThe address box that cost $1,900Your checkout suggests addresses as people type, using a maps API. Orders are steady, but this month's maps bill is $1,900.

Other trails

  • Who may see what

    Sign-in, permissions, and the leaks AI-built apps ship most often.

  • The life of a click

    Follow one button press from the browser to the database and back.

  • Money and secrets

    Keys, payments, webhooks, and reading what your AI changed.

  • Data you can lose

    Agents that reset production, backups that are a day old, rollbacks that break.

  • Working with your AI agent

    Dangerous commands, fix loops, deleted tests, prompt injection and invented packages.

  • Launch day

    Emails that never arrive, sign-in errors, timeouts, stale prices and connection limits.

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  1. Next up · Free · 4 minThe open summarise buttonYour app has a free 'summarise this PDF' button. Your AI bill says you made 2 million requests last night. You have 60 users.
  2. Stop 2 · Pro · 4 minA quiet week, a loud billAlmost nobody visited your site this week. Your hosting bill is forty times higher than usual.
  3. Stop 3 · Pro · 4 min500 signups overnightYou give every new account 50 free AI credits. You wake up to 500 new signups and no new customers.
  4. Stop 4 · Pro · 4 minThe update that updates itselfYou added a function that stamps 'updated_at' whenever a profile changes. By morning your database bill has a new digit.
  5. Stop 5 · Pro · 4 min2 million requests from one tabYou left your dashboard open overnight. Your database usage page shows 2 million requests from a single browser.
  6. Stop 6 · Pro · 4 minThe 40,000 SMS codesYour phone sign-in sends a code by SMS. Overnight it sent 40,000 codes to numbers in countries you do not serve.
  7. Stop 7 · Pro · 5 minThe 4 MB thumbnailYour marketplace shows 24 small product photos per page. On phones it takes ages to load, and your storage bill warns you are over your data transfer limit.
  8. Stop 8 · Pro · 5 minThe address box that cost $1,900Your checkout suggests addresses as people type, using a maps API. Orders are steady, but this month's maps bill is $1,900.