---
title: "Free x402 tools: checker and EIP-3009 verifier | Settlens"
description: "Free browser tools for x402 payments: check a PAYMENT-REQUIRED header against your spending policy and verify an EIP-3009 payment signature, offline."
url: https://settlens.com/tools
last_updated: 2026-10-13
---

# Free x402 tools

> **In short:** Settlens offers two free browser tools for x402: a payment request checker that answers pay, review or do_not_pay for a PAYMENT-REQUIRED header under your spending policy, and an EIP-3009 verifier that recovers the signer of a PAYMENT-SIGNATURE. Both run the public offline tools of the Settlens MCP server.

Check an x402 payment request before paying, and verify the signature of a payment after the fact. Both work in your browser and call the public Settlens MCP endpoint: no account, no wallet and no payment key.

[Check a payment request](https://settlens.com/tools/x402-checker) [Verify a signature](https://settlens.com/tools/eip-3009-verifier)

## Tools

- **[x402 checker](https://settlens.com/tools/x402-checker)**

  Free x402 checker: paste a PAYMENT-REQUIRED header and your spending policy to get pay, review or do_not_pay with every check. No wallet, no sign-up.

- **[EIP-3009 verifier](https://settlens.com/tools/eip-3009-verifier)**

  Free EIP-3009 signature verifier for x402: recover the signer of a PAYMENT-SIGNATURE and check its recipient, amount and time window offline. No RPC, no wallet.

## The same tools for agents

Each page calls one offline tool of `https://settlens.com/mcp` with what you paste. Agents and scripts call the same tools, and a few more, directly.

_Offline tools of the Settlens MCP server_

| Tool | What it does | In the browser |
| --- | --- | --- |
| [`evaluate_payment_requirements`](https://settlens.com/docs/mcp#evaluate_payment_requirements) | Decides pay, review or do_not_pay for a 402: validates PAYMENT-REQUIRED with @x402/core 2.28.0, checks the URL binding and applies your policy to each option. | [x402 checker](https://settlens.com/tools/x402-checker) |
| [`verify_payment_signature`](https://settlens.com/docs/mcp#verify_payment_signature) | Recovers the EIP-3009 signer of an exact EVM authorization offline and checks it pays the advertised payTo and amount inside its time window. | [EIP-3009 verifier](https://settlens.com/tools/eip-3009-verifier) |
| [`verify_solana_transaction`](https://settlens.com/docs/mcp#verify_solana_transaction) | Checks every ed25519 signer slot of a Base64 Solana transaction, legacy or versioned. An empty fee-payer slot is reported as pending, not as a failure. | MCP only |
| [`verify_report`](https://settlens.com/docs/mcp#verify_report) | Recomputes the SHA-256 integrity digest of a Settlens JSON report to show whether it was edited after it was generated. | MCP only |
| [`verify_attestation`](https://settlens.com/docs/mcp#verify_attestation) | Verifies the ed25519 signature of a Settlens evidence attestation and, given the report, that it covers that report. | MCP only |
| [`list_checks`](https://settlens.com/docs/mcp#list_checks) | Explains every check id: what it verifies, why it matters and how to fix it, optionally filtered by category or mode. | MCP only |

**Claude Code**

```shell
claude mcp add --transport http settlens https://settlens.com/mcp
```

The [MCP server page](https://settlens.com/mcp) explains how an agent acts on each decision. Pilot participants also get the [Settlens CLI](https://settlens.com/docs/cli), which scans live endpoints and facilitators.

## What happens to what you paste

Your browser sends it to the Settlens MCP endpoint, which computes the result in memory and keeps no copy of the content. Requests are limited to 60 per minute per IP address. The tools never need a private key or seed phrase: never paste one. See the [privacy notice](https://settlens.com/privacy#mcp-endpoint).

## Go beyond one request

A pilot assesses a paid endpoint or facilitator end to end: passive scan, CI gate, monitoring and signed evidence.

[Request a pilot](https://settlens.com/contact) [See the product](https://settlens.com/product)