Settle Payment

curl --request POST \
  --url https://api.example.com/v1/settle

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.example.com/v1/settle",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"net/http"
	"io"
)

func main() {

	url := "https://api.example.com/v1/settle"

	req, _ := http.NewRequest("POST", url, nil)

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

require 'uri'
require 'net/http'

url = URI("https://api.example.com/v1/settle")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)

response = http.request(request)
puts response.read_body

{
  "success": true,
  "transaction": null,
  "message": "Settlement completed successfully",
  "details": {
    "settlement_id": "stl_xyz789",
    "verification_id": "vrf_abc123",
    "settled_amount": "20000",
    "merchant_received": 20000,
    "fee_amount_wei": 10000,
    "fee_collection_status": "collected",
    "fee_tx_hash": "0x8f3e7d2a1b9c4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f",
    "settlement_tx_hash": "0x1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b",
    "fee_collected_first": true,
    "pricing_model": "flat_rate",
    "description": "$0.01 USDC fee collected from merchant's approved balance before settlement"
  }
}

{
  "error": {
    "code": "insufficient_allowance",
    "message": "Merchant must approve facilitator for USDC spending",
    "details": {
      "required": "10000",
      "available": "0",
      "merchant": "0xA821f428Ef8cC9f54A9915336A82220853059090",
      "treasury": "0x5D791e3554D0e83f171126905Bda1640Bf6f9A8B",
      "approval_command": "node approve-facilitator.mjs"
    }
  }
}

{
  "error": {
    "code": "fee_collection_failed",
    "message": "Could not collect $0.01 fee from merchant",
    "details": {
      "reason": "Insufficient USDC balance",
      "merchant_balance": "0",
      "required_fee": "10000"
    }
  }
}

{
  "error": {
    "code": "settlement_failed",
    "message": "FiatTokenV2: authorization is expired",
    "details": {
      "reason": "Authorization validBefore timestamp has passed",
      "validBefore": "1735689600",
      "currentTime": "1735780000"
    }
  }
}

{
  "error": {
    "code": "not_found",
    "message": "No verification found for this payment"
  }
}

POST

settle

Settle Payment

curl --request POST \
  --url https://api.example.com/v1/settle

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.example.com/v1/settle",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"net/http"
	"io"
)

func main() {

	url := "https://api.example.com/v1/settle"

	req, _ := http.NewRequest("POST", url, nil)

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

require 'uri'
require 'net/http'

url = URI("https://api.example.com/v1/settle")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)

response = http.request(request)
puts response.read_body

{
  "success": true,
  "transaction": null,
  "message": "Settlement completed successfully",
  "details": {
    "settlement_id": "stl_xyz789",
    "verification_id": "vrf_abc123",
    "settled_amount": "20000",
    "merchant_received": 20000,
    "fee_amount_wei": 10000,
    "fee_collection_status": "collected",
    "fee_tx_hash": "0x8f3e7d2a1b9c4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f",
    "settlement_tx_hash": "0x1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b",
    "fee_collected_first": true,
    "pricing_model": "flat_rate",
    "description": "$0.01 USDC fee collected from merchant's approved balance before settlement"
  }
}

{
  "error": {
    "code": "insufficient_allowance",
    "message": "Merchant must approve facilitator for USDC spending",
    "details": {
      "required": "10000",
      "available": "0",
      "merchant": "0xA821f428Ef8cC9f54A9915336A82220853059090",
      "treasury": "0x5D791e3554D0e83f171126905Bda1640Bf6f9A8B",
      "approval_command": "node approve-facilitator.mjs"
    }
  }
}

{
  "error": {
    "code": "fee_collection_failed",
    "message": "Could not collect $0.01 fee from merchant",
    "details": {
      "reason": "Insufficient USDC balance",
      "merchant_balance": "0",
      "required_fee": "10000"
    }
  }
}

{
  "error": {
    "code": "settlement_failed",
    "message": "FiatTokenV2: authorization is expired",
    "details": {
      "reason": "Authorization validBefore timestamp has passed",
      "validBefore": "1735689600",
      "currentTime": "1735780000"
    }
  }
}

{
  "error": {
    "code": "not_found",
    "message": "No verification found for this payment"
  }
}

Endpoint

Initiate settlement of a verified payment. The facilitator will:

Collect $0.01 fee from merchant’s approved USDC balance
Execute customer → merchant payment via 1Shot API

Fee Collection: The $0.01 fee is collected from the merchant’s pre-approved USDC balance BEFORE settlement execution.

Request Parameters

object

required

Same payment payload used in verification

object

required

Same payment requirements used in verification

Request Examples

curl -X POST https://facilitator.0xmeta.ai/v1/settle \
  -H "Content-Type: application/json" \
  -d '{
    "payment": {
      "x402Version": 2,
      "payload": {
        "authorization": {
          "from": "0x78b6b8c55d5ea96be6ca8213e61b0fa53e862480",
          "to": "0xA821f428Ef8cC9f54A9915336A82220853059090",
          "value": "20000",
          ...
        },
        "signature": "0x..."
      }
    },
    "requirements": {
      "scheme": "exact",
      "price": "$0.02",
      "network": "eip155:84532",
      "payTo": "0xA821f428Ef8cC9f54A9915336A82220853059090"
    }
  }'

const response = await fetch("https://facilitator.0xmeta.ai/v1/settle", {
  method: "POST",
  headers: {
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    payment: paymentPayload,      // From verification
    requirements: requirements    // From verification
  })
});

const data = await response.json();
console.log(data.success);        // true
console.log(data.details.settlement_id);

response = requests.post(
    'https://facilitator.0xmeta.ai/v1/settle',
    headers={'Content-Type': 'application/json'},
    json={
        'payment': payment_payload,
        'requirements': requirements
    }
)

data = response.json()
print(data['success'])
print(data['details']['settlement_id'])

Response Examples

{
  "success": true,
  "transaction": null,
  "message": "Settlement completed successfully",
  "details": {
    "settlement_id": "stl_xyz789",
    "verification_id": "vrf_abc123",
    "settled_amount": "20000",
    "merchant_received": 20000,
    "fee_amount_wei": 10000,
    "fee_collection_status": "collected",
    "fee_tx_hash": "0x8f3e7d2a1b9c4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f",
    "settlement_tx_hash": "0x1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d3e4f5a6b7c8d9e0f1a2b",
    "fee_collected_first": true,
    "pricing_model": "flat_rate",
    "description": "$0.01 USDC fee collected from merchant's approved balance before settlement"
  }
}

{
  "error": {
    "code": "insufficient_allowance",
    "message": "Merchant must approve facilitator for USDC spending",
    "details": {
      "required": "10000",
      "available": "0",
      "merchant": "0xA821f428Ef8cC9f54A9915336A82220853059090",
      "treasury": "0x5D791e3554D0e83f171126905Bda1640Bf6f9A8B",
      "approval_command": "node approve-facilitator.mjs"
    }
  }
}

{
  "error": {
    "code": "fee_collection_failed",
    "message": "Could not collect $0.01 fee from merchant",
    "details": {
      "reason": "Insufficient USDC balance",
      "merchant_balance": "0",
      "required_fee": "10000"
    }
  }
}

{
  "error": {
    "code": "settlement_failed",
    "message": "FiatTokenV2: authorization is expired",
    "details": {
      "reason": "Authorization validBefore timestamp has passed",
      "validBefore": "1735689600",
      "currentTime": "1735780000"
    }
  }
}

{
  "error": {
    "code": "not_found",
    "message": "No verification found for this payment"
  }
}

Response Fields

boolean

required

Whether settlement completed successfully

null

required

Always null (maintained for x402 compatibility)

string

required

Human-readable settlement result

object

details.settlement_id: Unique settlement identifierdetails.verification_id: Associated verification IDdetails.settled_amount: Amount settled (customer payment)details.merchant_received: Amount merchant received (same as settled_amount)details.fee_amount_wei: Fee collected from merchant (10000 = $0.01)details.fee_collection_status: “collected” | “failed”details.fee_tx_hash: On-chain transaction hash of fee collectiondetails.settlement_tx_hash: On-chain transaction hash of settlementdetails.fee_collected_first: Always true (guarantees no free service)details.pricing_model: “flat_rate”details.description: Explanation of fee collection method

Settlement Process

Settlement States

Fee Collection Details

Pre-Settlement Fee Collection

Why collect fee first? Prevents free service exploitation. If settlement executed before fee collection, merchants could intentionally cause settlement failures to get free verification service. Process:

// 1. Check merchant approval
allowance = USDC.allowance(merchant, treasury);
require(allowance >= 10000, "Insufficient allowance");

// 2. Collect fee FIRST
USDC.transferFrom(merchant, treasury, 10000);  // $0.01

// 3. THEN execute settlement
executeSettlement(authorization, signature);

If fee collection fails:

Settlement is blocked
Customer is NOT charged
Merchant receives error: insufficient_allowance or fee_collection_failed

If settlement fails after fee:

Merchant paid $0.01 for the attempt
This is intentional (prevents exploitation)

Handling Settlement Status

Polling for Completion

async function waitForSettlement(settlementId) {
  const maxAttempts = 60;  // 5 minutes

  for (let attempt = 0; attempt < maxAttempts; attempt++) {
    const response = await fetch(
      `https://facilitator.0xmeta.ai/v1/settlements/${settlementId}`
    );

    const settlement = await response.json();

    if (settlement.success && settlement.details.settlement_tx_hash) {
      console.log("✅ Settlement complete:", settlement.details.settlement_tx_hash);
      return settlement;
    }

    // Wait 5 seconds before next check
    await new Promise(resolve => setTimeout(resolve, 5000));
  }

  throw new Error("Settlement timeout");
}

Common Issues

Insufficient Allowance

Error: fee_collection_status: insufficient_allowanceSolution: Merchant must approve facilitator:

node approve-facilitator.mjs

Insufficient USDC Balance

Error: fee_collection_failed: Insufficient USDC balanceSolution: Merchant needs to add USDC to their addressCheck balance:

node check-allowance.mjs
# Shows: USDC Balance: 0.00 USDC ← Problem

Authorization Expired

Error: settlement_failed: authorization is expiredSolution: Customer needs to create new authorization with longer validity:

validBefore: String(Math.floor(Date.now() / 1000) + 86400)  // 24 hours

Authorization Already Used

Error: settlement_failed: authorization is used or canceledSolution: Generate new unique nonce for each payment:

const nonce = "0x" + Array.from(crypto.getRandomValues(new Uint8Array(32)))
  .map(b => b.toString(16).padStart(2, "0"))
  .join("");

Settlement Takes Long

Normal: 35-70 secondsBreakdown:

Fee collection: 5-10 seconds
Provider submission: 5-15 seconds
On-chain confirmation: 15-45 seconds

If longer: Check Base network status and Provider API status

On-Chain Verification

All transactions are publicly verifiable:

# Fee collection transaction
https://basescan.org/tx/{fee_tx_hash}

# Settlement transaction
https://basescan.org/tx/{settlement_tx_hash}

# Merchant address activity
https://basescan.org/address/{merchant_address}

Settlement Timing

Stage	Typical Duration
Fee Collection	5-10 seconds
Provider Submission	5-15 seconds
On-chain Confirmation	15-45 seconds
Total	35-70 seconds

Settlement typically completes in 35-70 seconds on Base. Use polling or webhooks to track status.

Merchant Economics

Per settlement:

Customer pays:        $0.02 (to merchant address)
Merchant receives:    $0.02 (100% of customer payment)
Fee collected:        $0.01 (from merchant's approved balance)
Net to merchant:      $0.01

Example: 1000 settlements

Gross revenue:        $20.00 (customer payments)
Facilitator fees:     $10.00 (collected via transferFrom)
Net revenue:          $10.00

Best Practices

Ensure Sufficient Approval

Before going live, verify merchant has approved enough USDC:

node check-allowance.mjs
# Should show: Settlements: 10000+ ✅

Maintain USDC Balance

Ensure merchant address has USDC for fees:

Minimum: 1 USDC (100 settlements)
Recommended: Match approval amount

Handle Errors Gracefully

Catch and display user-friendly error messages:

if (error.code === "insufficient_allowance") {
  alert("Merchant setup required. Please contact support.");
}

Monitor Settlements

Log settlement IDs and track success rates:

logger.info({
  settlement_id: settlement.details.settlement_id,
  fee_collected: settlement.details.fee_collection_status,
  settlement_tx: settlement.details.settlement_tx_hash
});

Next Steps

Verify Payment

Verify before settling

Error Handling

Handle settlement failures

Webhooks

Get settlement notifications

Architecture

Understand fee collection

Settlement complete! Customer payment delivered to merchant, fee collected from merchant’s approved balance.

Get Started

Micro Protocols

Guides

API Reference

Advanced

Support

Settle Payment

Endpoint

Request Parameters

Request Examples

Response Examples

Response Fields

Settlement Process

Settlement States

Fee Collection Details

Pre-Settlement Fee Collection

Handling Settlement Status

Polling for Completion

Common Issues

On-Chain Verification

Settlement Timing

Merchant Economics

Best Practices

Next Steps

Verify Payment

Error Handling

Webhooks

Architecture

​Endpoint

​Request Parameters

​Request Examples

​Response Examples

​Response Fields

​Settlement Process

​Settlement States

​Fee Collection Details

​Pre-Settlement Fee Collection

​Handling Settlement Status

​Polling for Completion

​Common Issues

​On-Chain Verification

​Settlement Timing

​Merchant Economics

​Best Practices

​Next Steps

Verify Payment

Error Handling

Webhooks

Architecture

Endpoint

Request Parameters

Request Examples

Response Examples

Response Fields

Settlement Process

Settlement States

Fee Collection Details

Pre-Settlement Fee Collection

Handling Settlement Status

Polling for Completion

Common Issues

On-Chain Verification

Settlement Timing

Merchant Economics

Best Practices

Next Steps