How to give your AI agent FLUX Kontext Pro

Way 1

Pay per call with x402 (no sign-up)

x402 is an open standard that puts payment into normal HTTP. The agent asks, the server answers with the price, and the agent's wallet signs a USDC payment and asks again. Best when the agent should pay for itself.

1. 1

   Give the agent a wallet with a little USDC on Base

   In Claude Code, Cursor or Codex, AgentCash sets up the wallet and adds every TollNode node as a tool. Run it once, then send a few dollars of USDC on the Base network to the address it shows.

   terminalCopy

   npx agentcash add https://tollnode.com

2. 2

   Ask your agent to use FLUX Kontext Pro

   Say what you want in plain words, for example “make an image of …”. The agent picks the FLUX Kontext Pro image editing node, sees the price and pays. From a terminal you can call it directly:

   terminalCopy

   npx agentcash@latest fetch https://tollnode.com/api/v1/nodes/flux-kontext-pro -m POST -b '{"prompt":"make it night time with neon lights","input_image":"https://tollnode.com/opengraph-image"}'

3. 3

   Or pay from your own code

   Any x402 client works. In JavaScript:

   javascriptCopy

   // npm i @x402/fetch @x402/evm viem
   import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
   import { registerExactEvmScheme } from "@x402/evm/exact/client";
   import { privateKeyToAccount } from "viem/accounts";
   
   const signer = privateKeyToAccount(process.env.AGENT_WALLET_KEY); // a wallet holding USDC on Base
   const pay = wrapFetchWithPayment(fetch, registerExactEvmScheme(new x402Client(), { signer }));
   
   const res = await pay("https://tollnode.com/api/v1/nodes/flux-kontext-pro", {
     method: "POST",
     headers: { "content-type": "application/json" },
     body: JSON.stringify({"prompt":"make it night time with neon lights","input_image":"https://tollnode.com/opengraph-image"}),
   });
   console.log(await res.json());

4. 4

   What happens on the wire

   The first request comes back as HTTP 402 with the exact price. The client signs and retries with a PAYMENT-SIGNATURE header. TollNode checks the signature, runs FLUX Kontext Pro image editing, and collects the payment only if the result is usable. A failed call is never settled.

   see the 402 yourselfCopy

   curl -i -X POST https://tollnode.com/api/v1/nodes/flux-kontext-pro \
     -H 'content-type: application/json' \
     -d '{"prompt":"make it night time with neon lights","input_image":"https://tollnode.com/opengraph-image"}'

Way 2

Account balance + API key

Load a balance once and use an ordinary API key. Best for apps, servers and teams, or code that can't sign payments.

1. 1

   Create a free account

   Sign up with your email. There is no monthly fee.

2. 2

   Add funds

   On your account page, pick $5, $10, $25 or $50 and confirm in a browser wallet such as Coinbase Wallet or MetaMask. You pay in USDC on Base, with no gas fee to pay.

3. 3

   Create an API key

   Name it after the agent or app that uses it. The key is shown once, so store it as an environment variable (TOLLNODE_API_KEY). You can revoke it at any time.

4. 4

   Call the node

   curlCopy

   curl -X POST https://tollnode.com/api/v1/nodes/flux-kontext-pro \
     -H "Authorization: Bearer $TOLLNODE_API_KEY" \
     -H "content-type: application/json" \
     -d '{"prompt":"make it night time with neon lights","input_image":"https://tollnode.com/opengraph-image"}'

   javascriptCopy

   const res = await fetch("https://tollnode.com/api/v1/nodes/flux-kontext-pro", {
     method: "POST",
     headers: {
       Authorization: `Bearer ${process.env.TOLLNODE_API_KEY}`,
       "content-type": "application/json",
     },
     body: JSON.stringify({"prompt":"make it night time with neon lights","input_image":"https://tollnode.com/opengraph-image"}),
   });
   console.log(await res.json());

   pythonCopy

   import os, requests
   
   r = requests.post(
       "https://tollnode.com/api/v1/nodes/flux-kontext-pro",
       headers={"Authorization": f"Bearer {os.environ['TOLLNODE_API_KEY']}"},
       json={"prompt":"make it night time with neon lights","input_image":"https://tollnode.com/opengraph-image"},
   )
   print(r.json())

   A successful call returns the result plus an x-tollnode-charged-usd header. If the balance is too low you get HTTP 402 with your balance and a top-up link, and nothing is charged. A wrong or revoked key returns 401.

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