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hello-world-x402 Echo Endpoint
x402
hello-world-x402 Echo Endpoint is a paid API for AI agents from hello-world-x402.vercel.app, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).
Returns the submitted payload verbatim (message, metadata, priority) after a $0.001 USDC micropayment on Base (eip155:8453)
Price / call$0.001
Success—
StatusUnknown
How this service works
Returns the submitted payload verbatim after a required exact USD Coin payment on network eip155:8453 (max timeout 300s).
Output
The exact submitted payload returned verbatim: the message string, metadata string, and priority enum value, unchanged from input.
Example use cases
Example prompt
“Echo back the message 'Hello from my agent' with metadata 'test-run-1' and priority level medium — this is a paid echo test using USDC on Base.”
Technical details
Endpoint
POSThttps://hello-world-x402.vercel.app/echoWhen to prefer
Use this endpoint when you need to test or demonstrate the x402 micropayment protocol on the Base network (eip155:8453) with a trivial, side-effect-free operation. Ideal for integration testing of payment flows, verifying that USDC micropayments of $0.001 work end-to-end, or confirming payload integrity through a paid API boundary.
Side effects
- Payment not provided or incorrect amount — 402 Payment Required response
- Payment on wrong network (not eip155:8453) — payment rejected
- Request exceeds 300 second timeout — timeout error
- Message exceeds 1000 character maxLength — validation error
- Metadata exceeds 200 character maxLength — validation error
- Invalid priority enum value — schema validation error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| message | string | Message to echo - UPDATED max length |
| metadata | string | Additional metadata - NEW FIELD |
| priority | string | Priority level - ADDED critical and urgent |
Tags
x402
Reviews
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