Echo a message: send a message and get it back, to test a paid call end to end

$0.01 per call · failed calls are never charged · no account or subscription: pay per call with a card key or USDC

Returns the message you send, with its length and the server time. Use to test an x402 client, payment flow or agent tool wiring end to end.

Run it free (25 free calls) Buy credits by card (from $1) Example result (JSON)

Try it with your own inputs

Message, up to 2,000 characters

Uses one of your 25 free calls. Nothing is charged, and a call that fails is not counted.

Inputs

NameTypeDescription
message (required)stringMessage, up to 2,000 characters

Request

Over HTTP, with a card key from /credits:

curl -H "Authorization: Bearer adt_…" "https://tools.funwords.eu/echo?message=hello"

Or one of your 25 free calls, no key:

curl "https://tools.funwords.eu/echo?message=hello&trial=1"

Without a key, the same URL answers 402 Payment Required with x402 and MPP terms, so an agent with a wallet pays per call in USDC (Base, Polygon, Arbitrum or Solana over x402; Base or Tempo over MPP) and retries.

Example result

{
  "message": "hello",
  "length": 5,
  "receivedAt": "2026-10-18T12:00:00.000Z"
}

From an AI agent (MCP)

Add the MCP server to Claude, Cursor or any MCP client. This tool is echo, and the first 25 successful calls are free:

https://tools.funwords.eu/mcp

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