Quote Bounds

curl "https://api-antseed.mrdn.finance/v1/antseed/topups/quote?buyer=0xYourAddress&amount=5000000&network=optimism"

{
  "buyer": "0xYourAddress",
  "amount": "5000000",
  "minAmount": "1750000",
  "maxAmount": "10000000",
  "balance": "0",
  "creditLimit": "10000000",
  "headroom": "10000000",
  "minBuyerDeposit": "1000000",
  "requirements": {
    "scheme": "exact",
    "network": "optimism",
    "extra": { "destinationChainId": 8453, "…": "…" },
    "…": "…"
  },
  "sources": [
    {
      "network": "base",
      "evmChainId": 8453,
      "minAmount": "1250000",
      "maxAmount": "10000000"
    },
    {
      "network": "optimism",
      "evmChainId": 10,
      "minAmount": "1750000",
      "maxAmount": "10000000"
    },
    {
      "network": "ink",
      "evmChainId": 57073,
      "minAmount": "1750000",
      "maxAmount": "10000000"
    }
  ]
}

GET

{merchant}

topups

quote

curl "https://api-antseed.mrdn.finance/v1/antseed/topups/quote?buyer=0xYourAddress&amount=5000000&network=optimism"

{
  "buyer": "0xYourAddress",
  "amount": "5000000",
  "minAmount": "1750000",
  "maxAmount": "10000000",
  "balance": "0",
  "creditLimit": "10000000",
  "headroom": "10000000",
  "minBuyerDeposit": "1000000",
  "requirements": {
    "scheme": "exact",
    "network": "optimism",
    "extra": { "destinationChainId": 8453, "…": "…" },
    "…": "…"
  },
  "sources": [
    {
      "network": "base",
      "evmChainId": 8453,
      "minAmount": "1250000",
      "maxAmount": "10000000"
    },
    {
      "network": "optimism",
      "evmChainId": 10,
      "minAmount": "1750000",
      "maxAmount": "10000000"
    },
    {
      "network": "ink",
      "evmChainId": 57073,
      "minAmount": "1750000",
      "maxAmount": "10000000"
    }
  ]
}

Returns the buyer’s merchant balance, credit limit, headroom, accepted amount range, and x402 payment requirements. This endpoint does not move funds.

Path

string

default:"antseed"

required

Merchant id. Currently antseed.

Query

string

required

Address to quote for (checksummed or lowercase).

string

Gross payment-token amount in 6-decimal base units. Defaults to the maximum available headroom. Invalid amounts return 400 amount_too_low, 400 amount_too_high, or 409 credit_limit_reached.

string

Optional payment source. Supported values are base, ethereum, arbitrum, bsc, hyperevm, ink, monad, optimism, polygon, robinhood, unichain, and worldchain. Defaults to Base. Unknown sources return 400 wrong_network.

Response fields

All amounts are 6-decimal base-unit strings. amount, minAmount, and maxAmount use the selected source token. Merchant balance fields use Base USDC.

Field	Meaning
`minAmount` / `maxAmount`	Accepted gross range for the selected source. Cross-chain minimums include a buffered Across fee quote (or the configured static fallback).
`balance`	Buyer’s current merchant-side balance (available + reserved).
`creditLimit`	Merchant-side credit limit for the buyer.
`headroom`	Remaining credit capacity (`creditLimit − balance`).
`minBuyerDeposit`	Merchant-side minimum applying to this top-up (`"0"` once the buyer has a balance).
`requirements`	The x402 payment requirements for the selected source. It corresponds to that source’s entry in a subsequent challenge.
`sources`	Sources that can accept the requested amount, as `{ network, evmChainId, minAmount, maxAmount }`.

curl "https://api-antseed.mrdn.finance/v1/antseed/topups/quote?buyer=0xYourAddress&amount=5000000&network=optimism"

The source list below is abbreviated; the live response includes every enabled source that can accept the requested amount.

{
  "buyer": "0xYourAddress",
  "amount": "5000000",
  "minAmount": "1750000",
  "maxAmount": "10000000",
  "balance": "0",
  "creditLimit": "10000000",
  "headroom": "10000000",
  "minBuyerDeposit": "1000000",
  "requirements": {
    "scheme": "exact",
    "network": "optimism",
    "extra": { "destinationChainId": 8453, "…": "…" },
    "…": "…"
  },
  "sources": [
    {
      "network": "base",
      "evmChainId": 8453,
      "minAmount": "1250000",
      "maxAmount": "10000000"
    },
    {
      "network": "optimism",
      "evmChainId": 10,
      "minAmount": "1750000",
      "maxAmount": "10000000"
    },
    {
      "network": "ink",
      "evmChainId": 57073,
      "minAmount": "1750000",
      "maxAmount": "10000000"
    }
  ]
}

Overview

x402 Payments

x402 Inference

Merchant Top-ups

Nanopayments Gateway

Path

Query

Response fields

​Path

​Query

​Response fields

Path

Query

Response fields