English Français العربية

Webhook Tester API

Official registry Other

Test webhook endpoints — send requests, measure latency, validate responses. x402 micropayment.

Source code Website Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

Remote (sse)
Claude Code 
claude mcp add --transport sse webhook-tester-api 'https://webhook-tester.api.klymax402.com/mcp'
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "webhook-tester-api": {
            "type": "sse",
            "url": "https://webhook-tester.api.klymax402.com/mcp"
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. Webhook Tester API
  2. Quickstart -- MCP
  3. Quickstart -- HTTP (x402)
  4. Tools
  5. Example agent prompts
  6. Payment
  7. Part of klymax402
  8. License

Webhook Tester API

Test webhook endpoints -- send POST/PUT/PATCH/DELETE with custom headers and payloads. Measure latency and TLS. Pay-per-call via x402 (USDC on Base L2) -- no API key, no signup, no rate-limit wall.

Part of the klymax402 marketplace -- 100 x402 micropayment APIs for AI agents, one wallet, USDC on Base.

Quickstart -- MCP

Add to your MCP client config (Claude Desktop, Cursor, ElizaOS, etc.):

{
  "mcpServers": {
    "webhook-tester": {
      "url": "https://webhook-tester.api.klymax402.com/mcp"
    }
  }
}

Quickstart -- HTTP (x402)

curl -X POST "https://webhook-tester.api.klymax402.com/api/test" \
  -H "Content-Type: application/json" \
  -d '{"url":"https://example.com"}'
# -> 402 Payment Required, with an x402 payment challenge in the response body

Any x402-aware client (@x402/fetch, x402-agent-tools, ATXP) handles the 402 -> sign -> retry cycle automatically.

Tools

ToolMethodPathPriceDescription
api_test_webhookPOST/api/test$0.005Send a test request to a webhook URL and analyze the response
api_test_webhook

Use this when you need to test a webhook endpoint by sending a request with custom headers, body, and method. Returns full response data in JSON.

Parameters

NameTypeRequiredDescription
urlstringyesWebhook URL to test (must be https)
methodstringnoHTTP method: POST, PUT, PATCH, DELETE (default: POST)
headersobjectnoCustom headers as key-value pairs
bodyobjectnoJSON body to send
timeoutnumbernoTimeout in seconds (default: 10, max: 30)

Example response:

{"url":"https://hooks.example.com/callback","method":"POST","statusCode":200,"responseBody":{"received":true},"latency":142,"tlsInfo":{"protocol":"TLSv1.3","cipher":"AES-256-GCM"},"requestSize":256,"responseSize":48}

When to use: testing webhook integrations, debugging API callbacks, validating endpoint availability, and measuring webhook response times.

Not for: web scraping (use web_scrape_to_markdown), screenshot capture (use capture_screenshot), HTTP header security audit (use network_analyze_headers).

Example agent prompts

  • "Test a webhook endpoint by sending a request with custom headers, body, and method"

Payment

  • Protocol: x402 -- HTTP-native pay-per-call, no signup, no API key
  • Network: Base L2 (eip155:8453)
  • Asset: USDC
  • Facilitator: Coinbase CDP (primary), PayAI (fallback)
  • Also reachable via ATXP (OAuth-wrapped x402, RFC 9728 protected-resource metadata)

Part of klymax402

100 x402 micropayment APIs for AI agents -- one wallet, USDC on Base, zero signup.

License

MIT

Frequently asked questions

What is Webhook Tester API?

Test webhook endpoints — send requests, measure latency, validate responses. x402 micropayment.

How do I install Webhook Tester API?

It runs as a remote server. In Claude Code: claude mcp add --transport sse webhook-tester-api 'https://webhook-tester.api.klymax402.com/mcp'. For other clients, paste the JSON configuration from this page into their MCP settings.

Does Webhook Tester API need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is Webhook Tester API open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains Webhook Tester API?

It is published by Br0ski777. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.