Webhooks - Miex Solutions API

Overview

Webhooks deliver HTTP POST requests to your endpoint whenever subscribed events occur. Each delivery is signed with HMAC-SHA256 so you can verify it came from the platform.

Supported Events

Event	Trigger
`order.created`	A new order is placed by a client
`order.status_changed`	An order’s status changes (any transition)
`order.cancelled`	An order is cancelled
`offer.updated`	An exchange rate offer is updated

Registering a Webhook

curl -X POST https://api.example.com/api/v1/partner/webhooks \
  -H "Authorization: Bearer sk_personal_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://your-app.com/hooks/exchange",
    "events": ["order.created", "order.status_changed"]
  }'

Response (secret shown once):

{
  "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "url": "https://your-app.com/hooks/exchange",
  "events": ["order.created", "order.status_changed"],
  "isActive": true,
  "secretKey": "a1b2c3d4...",
  "note": "Store this secret key securely — it will not be shown again."
}

Save secretKey immediately. Use it to verify HMAC-SHA256 signatures.

Verifying Signatures

Every delivery includes:

X-Webhook-Signature: sha256=<hmac>
X-Webhook-Event: order.created
X-Webhook-Delivery: <job-id>

Verify the signature before processing:

import * as crypto from 'crypto';

function verifySignature(rawBody: string, secret: string, signature: string): boolean {
  const expected = `sha256=${crypto
    .createHmac('sha256', secret)
    .update(rawBody)
    .digest('hex')}`;
  return crypto.timingSafeEqual(
    Buffer.from(expected),
    Buffer.from(signature),
  );
}

// Express example
app.post('/hooks/exchange', (req, res) => {
  const sig = req.headers['x-webhook-signature'] as string;
  const rawBody = JSON.stringify(req.body);

  if (!verifySignature(rawBody, process.env.WEBHOOK_SECRET!, sig)) {
    return res.status(401).json({ error: 'Invalid signature' });
  }

  // Process event
  const { event, data } = req.body;
  console.log(`Received ${event}:`, data);
  res.status(200).send('OK');
});

Payload Structure

All events share this envelope:

{
  "event": "order.created",
  "timestamp": "2026-02-26T12:00:00.000Z",
  "data": { /* event-specific object */ }
}

`order.created`

{
  "event": "order.created",
  "timestamp": "2026-02-26T12:00:00.000Z",
  "data": {
    "id": 1234,
    "status": "ORDERINIT",
    "amountSource": "1000",
    "amountDest": "26.5"
  }
}

`order.status_changed`

{
  "event": "order.status_changed",
  "timestamp": "2026-02-26T12:05:00.000Z",
  "data": { "id": 1234, "status": "CLIENTPAYMENTWAIT" },
  "status": "CLIENTPAYMENTWAIT"
}

`order.cancelled`

{
  "event": "order.cancelled",
  "timestamp": "2026-02-26T12:10:00.000Z",
  "data": { "id": 1234, "status": "CANCEL" }
}

Retry Policy

If your endpoint returns a non-2xx status or times out, the platform retries up to 5 times with exponential backoff:

Attempt	Delay
1	5 seconds
2	10 seconds
3	20 seconds
4	40 seconds
5	80 seconds

After 10 consecutive failures, the webhook is automatically deactivated to protect your endpoint. You can reactivate it via the dashboard or API.

Testing Webhooks Locally

Use a tunnel tool to expose your local server:

# Using ngrok
ngrok http 3001

# Register the tunnel URL as your webhook
curl -X POST https://api.example.com/api/v1/partner/webhooks \
  -H "Authorization: Bearer sk_personal_YOUR_KEY" \
  -d '{"url":"https://abc123.ngrok.io/hooks","events":["order.created"]}'

​Overview

​Supported Events

​Registering a Webhook

​Verifying Signatures

​Payload Structure

​order.created

​order.status_changed

​order.cancelled

​Retry Policy

​Testing Webhooks Locally

Overview

Supported Events

Registering a Webhook

Verifying Signatures

Payload Structure

`order.created`

`order.status_changed`

`order.cancelled`

Retry Policy

Testing Webhooks Locally