Payments

Overview

The Payments module lets you execute on-chain token transfers directly from your entity's Axiomatic smart wallet. Payments are submitted as ERC-4337 UserOperations, with gas fees sponsored by the Axiomatic paymaster — no ETH balance required.

Smart Wallet Architecture

Each entity in Axiomatic has a smart contract wallet deployed on-chain using the Diamond pattern (EIP-2535). The wallet is managed server-side — the platform constructs UserOperations, a paymaster sponsors gas, and a bundler submits the transaction to the network.

sequenceDiagram
    participant User
    participant PayPage as /pay Page
    participant API as /api/pay/execute
    participant Bundler
    participant Paymaster
    participant Wallet as Entity Smart Wallet
    participant Token as ERC-20 Contract

    User->>PayPage: Confirm payment details
    PayPage->>API: POST (entityId, token, amount, recipient)
    API->>API: Build UserOp calldata
    API->>Bundler: eth_sendUserOperation
    Bundler->>Paymaster: Validate + sponsor gas
    Bundler->>Wallet: Execute UserOp
    Wallet->>Token: transfer(recipient, amount)
    API-->>PayPage: userOpHash
    PayPage-->>User: Transaction submitted

Payment Types

The platform supports several payment intent types:

Payment Intent Lifecycle

Payment intents track the full lifecycle of an on-chain payment:

stateDiagram-v2
    [*] --> PENDING: Intent created
    PENDING --> SUBMITTED: UserOp sent to bundler
    SUBMITTED --> CONFIRMED: Transaction mined
    SUBMITTED --> FAILED: Transaction reverted
    PENDING --> EXPIRED: TTL exceeded (24h)

Using the Pay Page

Entry Points

The /pay page can be accessed in three ways:

Three-Step Flow

Step 1 — Select payment type:

• Pay a bill — choose from open bills with payCrypto enabled
• Upload a bill — upload a received invoice and enter vendor details
• Send a transfer — enter recipient address, amount, token, and chain

Step 2 — Confirm details:

Review recipient, amount, token, chain, and gas sponsorship before submitting.

Step 3 — Execute:

The payment is submitted to the bundler. You receive a UserOp hash for tracking.

From the AP Page

When you click Pay on a bill in the Payables page, it creates a payment intent and navigates to /pay?intent=<id>. The Pay page loads the intent details and presents the confirmation step.

Supported Tokens

API Reference

Execute Payment

POST /api/pay/execute

Execute a token transfer from the entity's smart wallet.

Request body:

{
  "entityId": "uuid",
  "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  "amount": "1000000",
  "recipient": "0x...",
  "chain": "base",
  "paymentIntentId": "uuid (optional)"
}

• amount is in the token's smallest unit (e.g. 1 USDC = 1000000 with 6 decimals)
• token set to 0x0000000000000000000000000000000000000000 for native ETH
• paymentIntentId links the payment to an existing intent and updates its status

Response:

{
  "success": true,
  "userOpHash": "0x...",
  "chain": "base",
  "from": "0x...",
  "to": "0x...",
  "token": "0x...",
  "amount": "1000000"
}

Error codes:

Payment Intents

GET /api/payment-intents?entityId=<uuid>
POST /api/payment-intents
PATCH /api/payment-intents

See the AR & AP documentation for the full payment intent API.