Tool detail

echo

Returns a JSON echo of an optional message string, paid in USDC — a minimal reference implementation of the x402 payment flow.

Categories: API testing

Use when

test that an x402 wallet and payment flow work end-to-end
verify a CDP facilitator integration with a trivial paid call

Not for

not the free /v1/free/echo connectivity check — this is the paid CDP version
not PageDelta's page-change detection — that's a separate, promoted product

Inputs

POST JSON body: { message: string, max 500 chars (optional) }

Admitted input schema

{
  "type": "object",
  "properties": {
    "message": {
      "type": "string",
      "minLength": 0,
      "maxLength": 500,
      "description": "Optional string to echo back in the response. Max 500 chars."
    }
  },
  "required": [],
  "additionalProperties": false
}

Endpoint

Method: POST
URL: https://app.heinrichstech.com/v1/cdp/echo

Payment

Protocol: x402
Listed price: 0.001 USDC per call on Base
Payment method: exact
Network: eip155:8453
Asset: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913

Listed terms are catalog metadata. The caller supplies inputs and calls the tool outside Onelayer. If payment is required, the caller uses a compatible wallet to pay.

Source

Directory: Coinbase x402 Bazaar
Record: POST https://app.heinrichstech.com/v1/cdp/echo
Retrieved: 2026-09-30T20:37:07.382Z
Catalog file SHA-256: 6837ccddf886f0007cf3727ea9d27faaa5047b51b4f425345c554ce1c271a524
Catalog built: 2026-09-30T22:31:58.034Z