Gemini generateContent (metered tier)

Google's native generateContent wire on the metered tier. Send Gemini's own request shape (contents, systemInstruction, generationConfig, function declarations) and get Gemini's own response shape (candidates, usageMetadata) back. Point a Google GenAI SDK at this gateway and pay per request with USDC, no account. Also answers the Google-shaped path /v1beta/models/<model>:generateContent.

TRY IN PLAYGROUND →

Input

Example output

{
  "candidates": [
    {
      "content": {
        "role": "model",
        "parts": [
          {
            "text": "x402 is an HTTP-native way for agents to pay per request with USDC."
          }
        ]
      },
      "finishReason": "STOP",
      "index": 0
    }
  ],
  "usageMetadata": {
    "promptTokenCount": 14,
    "candidatesTokenCount": 18,
    "totalTokenCount": 32
  },
  "modelVersion": "google/gemini-2.5-flash"
}

Try it - see the 402 challenge (free)

curl -i -X POST https://agent402.tools/v1/metered/gemini \
  -H "Content-Type: application/json" \
  -d '{"contents":[{"role":"user","parts":[{"text":"Summarize x402 in one sentence."}]}],"generationConfig":{"maxOutputTokens":256}}'

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";
import { metaTitle, metaDescription } from "./seo-meta.js";

const client = new x402Client();
client.setSpendControls?.(false); // @x402/core 2.23+ refuses anything over $1 or off the pegged-asset list by default; keep your own ceiling in code instead
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/v1/metered/gemini", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "contents": [
      {
        "role": "user",
        "parts": [
          {
            "text": "Summarize x402 in one sentence."
          }
        ]
      }
    ],
    "generationConfig": {
      "maxOutputTokens": 256
    }
  }),
});

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