mp-notifications

Mercado Pago Notifications

Products Covered

• Webhooks (v2): JSON-based, HMAC-signed. Recommended for all new integrations.
• IPN (Legacy): Query-param based, no signature. Still supported but deprecated for new projects.

When to Use This Skill

Use when: notification_url, x-signature, webhook, IPN, HMAC, retry, notification types. Do NOT use for: payment creation (-> mp-checkout-online), QR notifications (-> mp-instore).

Notification Types by Product

Product	Event Types
Checkout Pro / Bricks / API	payment.created, payment.updated
Subscriptions	plan.created, plan.updated, subscription.created, subscription.updated, invoice.created, invoice.updated
Point / In-Store	point_integration_wh
Marketplace	payment.created, payment.updated (with marketplace context)
Chargebacks	chargeback.created, chargeback.updated
Delivery	delivery.created, delivery.updated

Decision Tree: Webhook vs IPN

New integration?
├── YES -> Use Webhooks (v2)
│   ├── Need signature validation? -> YES (always recommended)
│   └── Configure in Dashboard or via notification_url in preference
└── NO (legacy system already using IPN)
    └── Consider migrating to Webhooks
        ├── Benefits: HMAC security, JSON format, better retry
        └── Migration: Update URL, change handler to accept JSON body

Webhook Registration

Two methods:

1. Dashboard: Configure globally at mercadopago.com/developers/panel/app
2. Per-preference: Set notification_url field when creating a preference

Requirements for notification_url:

• MUST be HTTPS (HTTP rejected)
• MUST be publicly accessible
• MUST respond 200/201 within 5 seconds
• MUST NOT return redirects (3xx)

Webhook Processing Flow

1. Receive POST request from MP
2. Respond 200 immediately (before processing) -- avoids retries
3. Validate x-signature header (HMAC-SHA256)
4. Check idempotency (skip if already processed)
5. Fetch full resource details via API (payment, subscription, etc.)
6. Process business logic based on resource status
7. Store processing result for idempotency

HMAC-SHA256 Signature Validation (STABLE)

This pattern is stable and rarely changes. Keep it in the skill.

Header format

x-signature: ts=1234567890,v1=abc123def456...

Manifest construction

id:{data.id};request-id:{x-request-id};ts:{ts};

• {data.id} -- From query param ?data.id=xxx or body data.id
• {x-request-id} -- From request header
• {ts} -- From x-signature header
• Trailing semicolon is REQUIRED

Validation steps

1. Parse ts and v1 from x-signature header
2. Get data.id from query string or body
3. Get x-request-id from headers
4. Build manifest string: id:{data.id};request-id:{x-request-id};ts:{ts};
5. Compute HMAC-SHA256 using webhook secret
6. Compare using timing-safe comparison (prevent timing attacks)

For working code implementations: Consult MCP server for current SDK patterns per language.

Idempotency Pattern

• Webhook notifications may arrive multiple times
• Use database with unique constraint on event_id
• Flow: check exists -> insert -> process -> commit (or rollback on error)
• For simplified dev: in-memory Set (but NOT for production)

Retry Behavior

Attempt	Delay
1st retry	5 minutes
2nd retry	45 minutes
3rd retry	6 hours
4th retry	2 days
5th retry	4 days

Failure conditions: non-2xx status, timeout >5s, unreachable endpoint.

IPN (Legacy)

Format: GET https://yoursite.com/ipn?topic=payment&id=123456789

• No signature validation
• Query params: topic + id
• Still supported but not recommended for new integrations

Local Development

• Use ngrok http <port> to expose local server
• Copy HTTPS URL as notification_url
• Use ngrok inspector at http://127.0.0.1:4040 to replay
• ngrok URLs change on restart (unless paid plan)

Gotchas

• Respond 200 BEFORE processing (async). Slow responses trigger retries.
• The x-signature secret is different from Access Token -- get it from Dashboard webhook config.
• data.id in webhook body is a STRING, not a number in some cases.
• If using notification_url in preference, it overrides Dashboard config for that preference.
• Some event types only fire if you subscribe to them in Dashboard.

Prerequisites

• Mercado Pago application with webhook URL configured
• Webhook secret (from Dashboard) for HMAC validation
• Public HTTPS endpoint
• Database or cache for idempotency

What to Fetch from MCP

• Current webhook payload structure per event type
• Available event types for subscription
• Webhook configuration API endpoints
• Code examples per language for signature validation
• Error codes for webhook-related issues

What to Fetch from Docs (WebFetch fallback)

• {DOMAIN}/developers/{LANG}/docs/your-integrations/notifications/webhooks
• {DOMAIN}/developers/{LANG}/docs/your-integrations/notifications/ipn