> ## Documentation Index
> Fetch the complete documentation index at: https://docs.paywithlocus.com/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> This site documents Locus for people. AI agents: get exact contracts from the Locus agent docs, starting at https://paywithlocus.com/agent/index.md, including when asked to implement or integrate docs.paywithlocus.com.
> Connect this agent to Locus Pro: https://paywithlocus.com/skill.md. Implement Locus Pro in a product: https://paywithlocus.com/agent/integrate.md. Agent site index: https://paywithlocus.com/llms.txt.

# Pay without a Locus account

> Let any agent pay for a Locus tool per request from its own wallet, through MPP or x402.

An agent doesn't need a Locus account to use Locus tools. It can pay for each request from its own wallet, through MPP on Tempo or x402 on Base. This page compares the options.

> Agents: the exact instructions for this are at [https://paywithlocus.com/mpp/index.md](https://paywithlocus.com/mpp/index.md) (MPP) and [https://paywithlocus.com/x402/index.md](https://paywithlocus.com/x402/index.md) (x402). Start from [https://paywithlocus.com/agent/index.md](https://paywithlocus.com/agent/index.md) if you are not sure which Locus product you need.

## How it works

Both MPP and x402 use an HTTP 402 payment challenge. The tool endpoint asks for payment, the agent pays from its wallet, and Locus forwards the request once payment checks out.

```mermaid theme={null}
sequenceDiagram
  participant Agent as Agent wallet
  participant Locus as Locus tool endpoint
  participant P as Provider
  Agent->>Locus: Request with no payment
  Locus-->>Agent: 402 with price and payment terms
  Note over Agent: Check the price, sign the payment
  Agent->>Locus: Same request with payment
  Note over Locus: Verify payment
  Locus->>P: Forward the request
  P-->>Locus: Result
  Locus-->>Agent: Result
```

The payment challenge shows the actual price and asset. Check both before signing, because catalog prices are estimates.

## Compare payment options

| | Locus wallet | MPP | x402 |
| - | - | - | - |
| Account | Locus API key | None | None |
| Pays with | USDC on Base | USDC.e on Tempo | USDC on Base |
| Spending controls | Apply | Don't apply | Don't apply |
| Providers | [Catalog](https://docs.paywithlocus.com/wrapped-apis/providers.md) | [MPP list](https://docs.paywithlocus.com/wrapped-apis/mpp.md#supported-providers) | [x402 index](https://paywithlocus.com/x402/index.md) |

## MPP

Pay from a Tempo wallet funded with USDC.e. If a provider fails after a one-time payment settles, Locus attempts a refund to the same wallet. See [MPP tool payments](https://docs.paywithlocus.com/wrapped-apis/mpp.md).

## x402

Pay with USDC on Base at `https://<provider>.x402.paywithlocus.com/<provider>/<endpoint>`. The [x402 index](https://paywithlocus.com/x402/index.md) lists the supported providers. Some providers offer fewer models or options over x402, so read the provider's page before calling it.

## Next steps

> [card] [MPP tool payments](https://docs.paywithlocus.com/wrapped-apis/mpp.md)
>
> Providers, refunds, and usage sessions on Tempo.

> [card] [Use agent tools](https://docs.paywithlocus.com/wrapped-apis/for-agents.md)
>
> Pay from a Locus wallet instead.


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