Test mode vs live mode

Blockchain0x runs two fully separated worlds. Test mode settles on Base
Sepolia with valueless test USDC; live mode settles on Base mainnet with real
USDC. Agents, payments, transactions, and webhooks never cross between them.

The same code targets both - you switch worlds by switching credentials, not by
rewriting calls.

What picks the mode

Two signals, and they must agree:

Your API key prefix. sk_test_* is a test-mode key; sk_live_* is a
live-mode key. See Authentication.
The X-Network header. Workspace-scoped requests carry X-Network, whose
value is testnet or mainnet. It scopes reads (responses are filtered to
that network) and stamps chain-bound writes.

The SDK manages the header for you. Pass network when you construct the client
and it is attached to every call that needs it:

const client = createClient({ apiKey: process.env.B0X_API_KEY! }); // sk_test_* -> testnet

You can also set it explicitly with createClient({ apiKey, network: 'testnet' })
(or 'mainnet'). If a workspace is locked to a single network for compliance, a
mismatched header is rejected with 403 network_locked.

Getting test USDC

A fresh test agent has no balance, and a test agent needs test USDC before it can
pay. Blockchain0x does not run its own faucet - fund the agent's address from
the public Base Sepolia faucets:

In the dashboard, a test-mode agent shows a Get test USDC button that links
straight to these. Live mode has no faucet - you fund mainnet agents with real
USDC.

Telling them apart

Test-mode chain notifications (email subject, push title) are prefixed
[TEST], so a test event is never mistaken for a real one.
Listing agents or transactions returns only the rows for the X-Network you
asked for. Switch the network and the list switches with it.

Going live

When you are ready for real money, swap the test key for an sk_live_ key and set
network: 'mainnet'. Nothing else in your integration changes. Walk the
Going live checklist first - idempotency, live-mode
webhook verification, and rate-limit handling all matter more once funds are real.