Live demo · No signup needed

Watch a runaway loop
not be your problem.

Three simulated AI tasks share one API key. The third has a bug — it never stops. Toggle UsageWall on and off. See your bill rise calmly with the wall, or spike out of control without it. $0.05 per call, ~GPT-4o pricing.

Whether the runaway is a buggy script, a curious tool, or your own forgotten cron job — without UsageWall it's your card that pays.

your tools

Three tools, one API key, $40 monthly cap

C
Cursor (you coding)
~ steady use
idle
0 calls $0.00
A
An agent (researching)
~ active
idle
0 calls $0.00
!
A cron job stuck in a loop 🐛
~ runaway
idle
0 calls $0.00

All three call OpenAI through your single API key. The cap is $40 across the whole month — your dollar limit, not per-tool.

the wall

Every call is metered before it goes through

your tools
CHECK
→ openai

No SDK. No code change. You swap your provider key for a UsageWall key in any tool that takes one — Cursor, ChatGPT clients, agents, scripts. Same shape, we just count the tokens before they pass.

your dashboard

What you see in real time

Your OpenAI spend this minute
$0.00
waiting for traffic…
Requests
0
Blocked
0
Saved
$0.00
No alerts yet. Run the simulation.
How it works in 4 steps

No code. Two minutes. One number to remember: your monthly cap.

  1. 01

    Paste your provider key

    Your OpenAI, Anthropic, Google, or DeepSeek key. We encrypt it at rest. You can rotate or revoke any time — the key never leaves our infrastructure once you save it.

  2. 02

    Set your monthly cap in dollars

    One number. "Never more than $40 this month." Optional alerts at 50%, 80%, 100%. Resets the 1st of every month or on the date you choose.

  3. 03

    Use the UsageWall key in your tools

    Cursor, ChatGPT clients, agents, your own scripts — anywhere that takes OPENAI_API_KEY. Same shape. Same models. We just count cents before each call goes through.

  4. 04

    You watch the meter. We pull the plug.

    Real-time spend dashboard. The instant a call would push you over your cap, we return "budget reached" instead of letting your card pay. Hard cap, not a polite warning.

Get early access → Back to home