Create a Seller account

Register a Seller account and create an API key. All three steps of the InFlow integration need them. Start in the sandbox.

Choose the correct account type

Account type	Use it for	Seller calls
Seller account	A service that takes payments with `@inflowpayai/mpp-seller` or `@inflowpayai/x402-seller`	Work
Developer account	An agent that only buys, with an API key	Fail with `403 SELLER_ACCOUNT_REQUIRED`

A Developer account key authenticates, but the seller configuration APIs need a Seller account.

Choose an environment

Each environment has its own dashboard, its own accounts, and its own keys.

Environment	Dashboard	SDK value	CLI flag
Sandbox	sandbox.inflowpay.ai	`environment: 'sandbox'`	`--sandbox`
Production	app.inflowpay.ai	`environment: 'production'`	none. This is the default.

A key works only in the environment that issued it. The environment value in your code must match the dashboard of the key.

The sandbox alone does not guarantee that a target or a blockchain uses test money. Check each network and asset before you pay.

Register and create a key

Open sandbox.inflowpay.ai. Register a Seller account.

Create an API key

Create an API key in the dashboard. This key is your INFLOW_API_KEY.

Store the key with its environment

Put the environment name and the key in the same .env file. They must always change together.

.env

INFLOW_ENVIRONMENT=sandbox
INFLOW_API_KEY=your_sandbox_key_here

Add .env to .gitignore. Never commit a key.

Check the key at startup

Catch a wrong account type at startup and stop with a clear message. For x402, createInflowSellerClient makes authenticated calls when you construct it, so the error appears at startup. For MPP, the inflow method loads its configuration in the background, so the error appears at the first paid request.

import { InflowApiError } from '@inflowpayai/x402';

try {
  await startSeller();
} catch (error) {
  if (error instanceof InflowApiError && error.code === 'SELLER_ACCOUNT_REQUIRED') {
    throw new Error('Configure a Seller account API key for this integration.');
  }
  throw error;
}

startSeller is your own startup function. For 401 and other errors, see Errors.

Keep keys safe

Keep production keys in the secret manager of your deployment. Never commit them.
Do not put a key in a chat, a plan file, or an issue.
Rotate a key if it appears outside your secret manager.

Next step

Protect an endpoint

Accept MPP and x402 on an endpoint with InFlow Payments.

Overview

Pay as an agent

Integrate your service

Concepts

Reference

Create a Seller account

Choose the correct account type

Choose an environment

Register and create a key

Check the key at startup

Keep keys safe

Next step

Protect an endpoint

​Choose the correct account type

​Choose an environment

​Register and create a key

​Check the key at startup

​Keep keys safe

​Next step

Protect an endpoint

Choose the correct account type

Choose an environment

Register and create a key

Check the key at startup

Keep keys safe

Next step