Metr Merchant Payments

Manage your Metr merchant account — start payment sessions, end (settle) them, and withdraw funds to your wallet.

What is Metr?

Metr is a multi-chain payment protocol that lets merchants accept crypto (USDC, SOL, POL, ETH, and custom SPL/ERC-20 tokens) via session-based checkout. Funds are held in escrow during a session and released when the session ends.

• Website: https://metrpay.com
• API Base: https://api.metr.app/v1

Prerequisites

1. A Metr merchant account (sign up at https://metrpay.com)
2. Your Merchant API Key — found in your Metr dashboard under Settings → API Keys
3. (Optional) An Agent Key if you want to run agentic checkout sessions

Authentication

All API calls require headers:

| Header | Value | When | |--------|-------|------| | x-api-key | Your merchant API key | All merchant endpoints | | x-agent-key | Your agent key | Agent session endpoints |

Store your key securely in Bankr:

• Open the Bankr terminal sidebar → click Advanced → click Env Vars
• Add METR_MERCHANT_API_KEY = your merchant key
• Add METR_AGENT_KEY = your agent key (if using agent sessions)

Core Operations

1. Start a Payment Session

Initiate a checkout session for a customer.

Endpoint: POST /v1/integrate/sessions/start

Headers:

• Content-Type: application/json
• x-api-key: <your-merchant-key>

Body:

json
{
  "amount": "10.00",
  "currency": "USDC",
  "chain": "base",
  "metadata": {
    "orderId": "order_12345",
    "customerEmail": "customer@example.com"
  }
}

Response:

json
{
  "sessionId": "sess_abc123",
  "paymentUrl": "https://pay.metr.app/sess_abc123",
  "status": "pending",
  "expiresAt": "2026-07-01T12:00:00Z"
}

Bankr CLI equivalent:

bash
curl -X POST https://api.metr.app/v1/integrate/sessions/start \
  -H "Content-Type: application/json" \
  -H "x-api-key: $METR_MERCHANT_API_KEY" \
  -d '{
    "amount": "10.00",
    "currency": "USDC",
    "chain": "base",
    "metadata": {"orderId": "order_12345"}
  }'

2. End (Settle) a Session

Release escrowed funds to the merchant wallet once the order is fulfilled.

Endpoint: POST /v1/integrate/sessions/{sessionId}/end

Headers:

• Content-Type: application/json
• x-api-key: <your-merchant-key>

Body:

json
{
  "reason": "fulfillment_complete",
  "metadata": {
    "deliveredAt": "2026-07-01T10:30:00Z"
  }
}

Response:

json
{
  "sessionId": "sess_abc123",
  "status": "settled",
  "settledAt": "2026-07-01T10:30:05Z",
  "txHash": "0x..."
}

Bankr CLI equivalent:

bash
curl -X POST "https://api.metr.app/v1/integrate/sessions/$SESSION_ID/end" \
  -H "Content-Type: application/json" \
  -H "x-api-key: $METR_MERCHANT_API_KEY" \
  -d '{"reason": "fulfillment_complete"}'

3. Start an Agent Session

For AI-agent-initiated payments (e.g., an agent buying a service on behalf of a user).

Endpoint: POST /v1/agents/sessions/start

Headers:

• Content-Type: application/json
• x-api-key: <your-merchant-key>
• x-agent-key: <your-agent-key>

Body:

json
{
  "amount": "5.00",
  "currency": "USDC",
  "chain": "solana",
  "agentId": "agent_001",
  "metadata": {
    "service": "api_call",
    "tier": "premium"
  }
}

4. End an Agent Session

Endpoint: POST /v1/agents/sessions/{sessionId}/end

Headers:

• Content-Type: application/json
• x-api-key: <your-merchant-key>
• x-agent-key: <your-agent-key>

Body:

json
{
  "reason": "service_delivered",
  "metadata": {}
}

Claim & Withdraw Funds

Metr does not expose a direct "claim" API endpoint. Instead:

1. Settlement = Claim: Ending a session automatically releases the escrowed funds to your configured merchant wallet. The txHash in the end-session response is your on-chain proof.

1. Withdraw from Dashboard: For bulk withdrawals or moving funds to a different wallet:

• Log in to https://metrpay.com/dashboard
• Go to Balances
• Select the chain/token you want to withdraw
• Enter your destination wallet address
• Confirm the withdrawal (on-chain tx will be sent)

1. Webhook Notifications: Set up a webhook in your Metr dashboard to receive real-time events:

• session.settled — funds released to merchant wallet
• withdrawal.completed — manual withdrawal finished

Supported Chains & Tokens

| Chain | Native Token | Stablecoins | Custom Tokens | |-------|-------------|-------------|---------------| | Solana | SOL | USDC | SPL tokens | | Polygon | POL | USDC | ERC-20 tokens | | Base | ETH | USDC | ERC-20 tokens |

Error Handling

Common HTTP status codes from Metr API:

| Code | Meaning | Action | |------|---------|--------| | 400 | Bad Request | Check request body schema | | 401 | Unauthorized | Verify x-api-key is correct | | 403 | Forbidden | Key lacks permission for this action | | 404 | Session Not Found | Double-check sessionId | | 409 | Session Already Ended | Idempotency — session is already settled | | 422 | Validation Error | Amount too small, unsupported chain, etc. | | 500 | Internal Error | Retry or contact Metr support |

Full Workflow Example

1. Customer places order on your site
2. You call POST /v1/integrate/sessions/start
3. You redirect customer to paymentUrl
4. Customer pays via Metr checkout
5. You fulfill the order (ship product, run service, etc.)
6. You call POST /v1/integrate/sessions/{id}/end
7. Funds are released to your merchant wallet
8. (Optional) You withdraw from dashboard to cold storage

References

• Metr Website: https://metrpay.com
• API Base: https://api.metr.app/v1
• Dashboard: https://metrpay.com/dashboard