Comparing Email APIs for AI Agents: Postmark, Resend, SendGrid, and Piisend

1import requests
2import json
3 
4api_key = "YOUR_API_KEY"
5url = "https://api.piisend.com/api/v1/emails"
6headers = {
7    "Authorization": f"Bearer {api_key}",
8    "Content-Type": "application/json"
9}
10payload = {
11    "to": ["recipient@example.com"],
12    "subject": "Your AI Agent Update",
13    "html": "<strong>Hello from your AI agent!</strong> Here is your update.",
14    "text": "Hello from your AI agent! Here is your update."
15}
16 
17response = requests.post(url, headers=headers, data=json.dumps(payload))
18 
19if response.status_code == 200:
20    print("Email sent successfully!")
21    print(response.json())
22else:
23    print(f"Failed to send email: {response.status_code}")
24    print(response.text)

1curl -X POST https://api.piisend.com/api/v1/emails \
2  -H "Authorization: Bearer YOUR_API_KEY" \
3  -H "Content-Type: application/json" \
4  -H "Idempotency-Key: unique-transaction-id-12345" \
5  -d '{
6    "to": ["user@example.com"],
7    "template_id": "welcome-email-template",
8    "template_vars": {
9      "user_name": "Alice",
10      "login_link": "https://app.example.com/login"
11    }
12  }'

1const crypto = require('crypto');
2const express = require('express');
3const bodyParser = require('body-parser');
4 
5const app = express();
6const webhookSecret = "YOUR_WEBHOOK_SECRET"; // Set this in your Piisend dashboard
7 
8app.use(bodyParser.json({
9    verify: (req, res, buf) => {
10        req.rawBody = buf; // Store raw body for signature verification
11    }
12}));
13 
14app.post('/webhook', (req, res) => {
15    const signature = req.headers['x-webhook-signature'];
16    const timestamp = req.headers['x-webhook-timestamp'];
17    const payload = req.rawBody;
18 
19    if (!signature || !timestamp || !payload) {
20        return res.status(400).send('Missing webhook headers or body');
21    }
22 
23    const signedPayload = `${timestamp}.${payload.toString()}`;
24    const expectedSignature = crypto
25        .createHmac('sha256', webhookSecret)
26        .update(signedPayload)
27        .digest('hex');
28 
29    if (signature !== expectedSignature) {
30        console.warn('Webhook signature mismatch!');
31        return res.status(403).send('Invalid signature');
32    }
33 
34    console.log('Webhook received and verified:', req.body);
35    // Process the event, e.g., update AI agent's state
36    res.status(200).send('OK');
37});
38 
39app.listen(3000, () => console.log('Webhook server listening on port 3000'));