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

# Client Introduction

> Choose an x402 client for TypeScript, Python or Go, configure payment authority, and handle paid HTTP responses.

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## Pay for an HTTP resource

An x402 client handles a resource server's payment challenge and submits a payment authorization with its retry. It needs a supported signer, sufficient funds and permission to spend; an ordinary HTTP client does not make payments automatically.

If you want to charge for a resource instead, start with the [merchant guide](/x402/servers/introduction). For a first end-to-end example, use the [quickstart](/x402/quickstart).

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## Choose your client

Follow one complete guide for its installation, signer setup and supported payment schemes. Do not combine snippets from different SDK generations.

| Your application uses | Start here |
| - | - |
| TypeScript with Fetch | [Fetch client](/x402/clients/typescript/fetch) |
| TypeScript with Axios | [Axios client](/x402/clients/typescript/axios) |
| Python with httpx | [httpx client](/x402/clients/python/httpx) |
| Python with requests | [requests client](/x402/clients/python/requests) |
| Go with net/http | [Go HTTP client](/x402/clients/go/http) |
| A custom TypeScript payment flow | [TypeScript manual flow](/x402/clients/typescript/manual-flow) |
| A custom Python payment flow | [Python manual flow](/x402/clients/python/manual-flow) |

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## Understand the payment flow

<img src="https://mintcdn.com/payai/2DGsVUJGFkMxMKTt/images/x402-sequence-diagram.svg?fit=max&auto=format&n=2DGsVUJGFkMxMKTt&q=85&s=750a29402143e49980393d116826ef2d" alt="x402 sequence diagram" width="1992" height="1570" data-path="images/x402-sequence-diagram.svg" />

For an ordinary exact-payment flow, the server returns a 402 challenge, the client selects acceptable payment terms and retries with a payment authorization, and the server coordinates verification, settlement and resource delivery. See the [x402 reference](/x402/reference) for the v2 headers and message shapes.

Check that the client and server support the same network, token and payment scheme. Network-fee sponsorship and any account setup costs depend on that combination; they are not a guarantee that every payment flow is free of network costs. See [supported networks](/x402/supported-networks).

End-to-end response time also includes application work, network transport and the integration's settlement behavior. The HTTP status code does not promise sub-second settlement.

## Before using real funds

* Protect signing keys: do not put private keys in public frontend code or commit them to source control.
* Set spending limits appropriate to the resource and check the advertised amount, network and recipient before authorizing payment.
* Check both payment and resource-delivery outcomes. A failed HTTP response does not prove that a payment did not settle; use the [capacity and recovery guidance](/x402/facilitators/capacity-and-limits) before retrying an uncertain payment.
* Treat [Solana batch settlement](/x402/servers/batch-settlement) as a separate public-preview facilitator integration with matching official `@x402/core` and `@x402/svm` versions, funded channels and its own recovery procedure, not a drop-in replacement for an exact-payment client.

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