Memory write

Persistent key-value memory for agents, scoped to the paying wallet. Your x402 payment IS your authentication: the wallet that pays owns the namespace. No signup, no API keys. Body: {"key":"…","value":any JSON,"ttlSeconds":3600?} to write (optional TTL), or {"key":"…","delete":true} to remove. Add "owner":"0x…" to write into another wallet's namespace you've been granted. Values up to 64KB.

Input

Example output

{
  "key": "research/task-42",
  "bytes": 42,
  "updated": 1760000000000,
  "expiresAt": 1760086400,
  "owner": "0x…",
  "persistent": true
}

Try it - see the 402 challenge (free)

curl -i -X POST https://agent402.tools/api/memory \
  -H "Content-Type: application/json" \
  -d '{"key":"research/task-42","value":{"status":"done","findings":["…"]},"ttlSeconds":86400}'

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/memory", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "key": "research/task-42",
    "value": {
      "status": "done",
      "findings": [
        "…"
      ]
    },
    "ttlSeconds": 86400
  }),
});

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