Every Chain PipRail Supports for x402 Payments

Most payment SDKs answer “which chains do you support?” with a list they maintain — an allowlist, baked into a release, that grows one pull request at a time. PipRail answers it differently: chain details are data the caller passes, not an allowlist the SDK ships. The built-in presets are a convenience — each comes with its canonical USDC address already filled in — but they are not a fence. Name a preset, or hand the SDK a chain it has never seen, and it pays either way.

That is the whole idea behind one parameter. The chain: value you pass selects the network, its sensible RPC default, the native coin, and the right stablecoin addresses — all at once. Going from Base to Solana, or from Polygon to the XRP Ledger, is a one-word change in your code and nothing else.

// A built-in preset — the canonical USDC address is pre-filled for you:
new PipRailClient({ chain: 'base', wallet: { key } })

// Switch chains by changing one word:
new PipRailClient({ chain: 'solana', wallet: { key } })

// Any other EVM chain works too — pass a viem Chain or a plain { id, rpcUrl }:
new PipRailClient({ chain: { id: 100, rpcUrl: '…' }, wallet: { key } })

The 20 EVM mainnets

Every major EVM chain is a built-in preset, with its Circle-native USDC pre-filled. If a chain you want is not in this list, you do not wait for us to add it — you pass it as a viem Chain or a bare { id, rpcUrl }, and it just works.

The nine non-EVM families

This is where breadth stops being a number and starts being an advantage. PipRail does not just speak EVM — it puts the payer’s own wallet on Solana, TON, Tron, NEAR, Sui, Aptos, Algorand, Stellar and the XRP Ledger, each as a self-contained driver that mirrors the others file-for-file. The libraries for these chains are optional peers that load only when you name one, so a pure-EVM install never pays for them.

A few of these chains have a one-time receive prerequisite, and PipRail is honest about it rather than failing silently: NEAR and Algorand need a one-time token registration on the recipient, Stellar and the XRP Ledger need a trustline and an activated account, and the planPayment() call surfaces exactly that with a RECIPIENT_NOT_READY blocker and a one-line funding hint. Paying with the native coin sidesteps all of it.

The tokens, in one rule

You do not have to memorize a matrix. The coverage follows a simple rule, and everything else is an address away:

Why breadth is the point

An agent does not get to choose what it holds when it meets a paywall. It holds what it holds — maybe USDC on Base, maybe SOL on Solana, maybe XRP because that is where its budget lives. A rail that only speaks one chain forces a bridge, a swap, and a wait before the agent can do the one thing it was asked to do: pay and move on. A rail that speaks twenty-nine lets it pay with what it has.

That is why PipRail treats chains as data and not as a gate. The list above is what ships today, verified address by verified address — but the design is built so the list is never the limit. Name a chain. If we have a preset, you get USDC for free. If we do not, pass it in. Either way, your agent pays.