The policy layer for agent payments

A spending limit your AI agent can't break.

Autonomous agents are starting to pay for things on their own — APIs, data, services. PayPerimeter sits between the agent and its wallet. You set the rules; the blockchain enforces the ceiling. Even if our software is bypassed entirely, the loss is bounded.

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Try it live → set a cap and turn the agent loose.

Live policy simulator

Spent today $0.00 / $1.00

Set a daily cap, then let the agent run.

Daily cap $1.00

// every decision lands in a signed, tamper-evident log

The problem

An agent with a wallet has no natural stopping point.

Software fails in ways people don't. It doesn't get tired, hesitate, or notice that something feels wrong — it just repeats, at machine speed, until something stops it.

Bugs don't stop at one

A human makes a mistaken purchase once. A looping agent makes the same mistaken purchase hundreds of times a minute, and nothing in the payment rails objects.

Prompts can be hijacked

An agent that reads the open web can be talked into things by the content it reads. If that agent also holds a key, persuasion becomes spending.

Rules in software can be skipped

A limit written in the same program the agent runs is a limit the agent can route around. Real enforcement has to live somewhere the agent can't reach.

How it works

Two layers. One of them can't be argued with.

Your funds sit in a vault the agent never touches. PayPerimeter releases small amounts to the agent's spending key — and the maximum it can ever release is fixed on-chain, by an audited contract, not by us.

Layer 1 · The runtime brake

Policy, evaluated on every payment

Before anything is signed, PayPerimeter checks the payment against the rules you wrote.

Spending caps per payment, hour, day, and week
Rate limits and repeat-payment (loop) detection
Per-vendor budgets, so one supplier can't drain another's
Human approval for anything above a threshold
An emergency stop that cuts everything instantly

Layer 2 · The hard ceiling

A cap the blockchain enforces

The vault grants PayPerimeter permission to move at most a fixed amount per period. That rule lives in an audited smart contract.

The agent's key only ever holds a small working balance
Exceeding the cap isn't refused by our code — it's refused by the network
Worst case, even fully compromised, is bounded by the cap
A compromised key can be revoked on-chain in one transaction

The point isn't that we promise to stop overspending. It's that past a certain number, there is nothing left to promise — the payment simply cannot happen.

Where we are

Built, and proven on a live network.

This isn't a concept. The full system runs end to end on Base Sepolia today — real payments, real on-chain caps, real refusals when an agent tries to go past them.

LiveWorking end to end on Base Sepolia testnet

BoundedBypass attempts refused by the contract itself

VerifiableEvery decision in a signed, tamper-evident log

Tested80 automated tests across the policy engine

Stated plainly: PayPerimeter is early. Everything above runs on a test network, not with real money, and the code has not yet been through an external security audit. We'd rather tell you that up front than have you find out later — a company built on enforcing limits should be honest about its own.

What's next

Where we think this goes.

Agents paying for things is going from a demo to a default. When that happens, the question stops being should this be governed and becomes what is actually enforcing it.

Today

The enforcement core

The policy engine, the signed audit log, and on-chain spending caps — working together, proven on testnet.

Real money, real teams

An external audit, then live networks. Alongside it: the dashboard a team needs to set policy, review approvals, and watch what their agents are actually spending.

The goal

The layer underneath

Every autonomous agent trusted with money needs something enforcing its limits and recording what it did — the way a compliance system sits under every employee with a company card. We want to be that layer.