Can Someone Run Up Your AI Chat Bill? How AskMerra Stops It

Every answer an AI assistant writes costs a little money. That is fine when the questions come from real shoppers, because they are the conversations you want. But a chat widget is public by design. Anyone can open your store, find the widget and send it messages, and so can a script that sends thousands of them.

So before you put any AI chat on your store, ask the vendor a simple question: what stops someone from running up my bill? This article answers it for AskMerra, layer by layer, and then shows the controls you have yourself.

Why a public widget needs protection

A chat widget has to work for anonymous visitors, so it cannot ask for a password. Whatever the browser sends to prove it is a real visitor, a determined script can imitate. No single check is enough.

AskMerra's approach is to stack several layers, each of which makes abuse more expensive, easier to spot or strictly limited in what it can cost. Most visitors never notice any of them.

Six layers between a script and your budget

1. Domain lock

Your site key works only on the domains you list in the dashboard. Requests that claim to come from any other site are rejected, and browsers on other sites do not even get permission to call the API. Copying your snippet to another website does nothing.

2. Browser screening

Requests that do not look like a real browser, such as command-line tools, scripting libraries or requests without the metadata modern browsers always send, are filtered out before they reach the AI.

3. Proof-of-work sessions

Before the first message, the widget solves a small cryptographic puzzle. For a real visitor this takes a fraction of a second and happens in the background. The widget then receives a signed session that lasts a short time and is bound to your shop, the visitor and the page. A script that wants a thousand sessions has to solve a thousand puzzles, which turns cheap abuse into expensive abuse.

4. Rate limits

Limits apply per visitor, per IP address and per shop. IP addresses are stored only as a hash, never in plain text. The defaults are generous for people and tight for scripts:

What	Default limit
Messages per visitor	20 per minute
Messages per IP address	60 per minute
Messages per shop	600 per minute
New conversations per visitor	30 per day
New conversations per IP address	60 per day
Widget sessions per IP address	60 per hour

Rotating visitor ids does not reset them.

5. Spend circuit breakers

If something gets through anyway, the circuit breakers notice the spike:

What	Threshold	What happens
AI cost per shop	$5 per hour	Protection mode for 60 minutes
AI cost per shop	$25 per day	Protection mode until midnight UTC
New conversations per shop	500 per hour	Protection mode for 60 minutes

In protection mode, your store keeps working and so does part of the assistant. Free answers continue: greetings, your FAQ and cached answers. Everything else gets a polite "we're busy" message with the contact form, so a real shopper can still reach you. You get one email about it, and you can resume the assistant from the dashboard at any time. A platform-wide breaker protects every shop at once on top of that.

6. Spending caps

The last layer is the one you control, and it is a hard ceiling: your included usage and your optional monthly spending cap. Whatever happens in the layers above, AI answers stop there.

The controls you have

AskMerra is priced on the AI work your assistant actually does. Your plan fee is included usage you can spend each month. Above it, you pay as you go at the same rates from prepaid credits. You decide how far that goes:

• Spending cap. Set a monthly maximum for pay-as-you-go. When it is reached, AI answers pause until the next period.
• Pay-as-you-go off. If you prefer, stop at your included usage. Nothing is ever charged beyond it.
• Prepaid credits. Pay-as-you-go is paid from credits you buy in advance, in euros, from €20. You can never owe more than you put in. Automatic top-up is optional and off unless you turn it on.
• Live usage. The dashboard shows your usage in euros as it happens, not at the end of the month.

When AI answers pause, the assistant does not go dark. Greetings, FAQ answers and cached answers keep working, and shoppers can still reach you through the contact form.

Some of the cheapest protection is simply answering well. Greetings, thank-yous and "are you a bot?" are free. Answers from your FAQ and from the answer cache cost almost nothing, because they need no AI call. Our guide on reducing support tickets shows how to set up FAQ entries that answer the most common questions instantly. For comparison, a typical conversation that does need the AI costs about €0.04.

What your shoppers notice

Almost nothing, and that is the point. The puzzle runs in the background in a fraction of a second. Rate limits sit far above what a person can type. Shoppers who use the chat normally never see a limit, and if your shop is ever in protection mode, they still get a friendly answer and a way to contact you.

Questions to ask any AI chat vendor

Whichever tool you choose, these questions are worth asking before you go live:

1. Can my site key be used on other websites?
2. What stops a script from opening thousands of sessions?
3. Are there limits per visitor and per IP address, and what are they?
4. What happens automatically if costs spike in the middle of the night?
5. Can I set a hard monthly cap, and what do shoppers see when it is reached?
6. Can I see my usage while it happens?

AskMerra's answers are on our security page, with the technical details in the security documentation. For plans and included usage, see pricing. If you want to talk it through, book a demo, or create your account and look at the usage dashboard yourself.