FetchHook vs. Ngrok: Why AI Agents need Mailboxes, not Tunnels

# No tunnel needed. No live process required.
curl https://api.fetchhook.app/api/v1/stash_abc123 \
  -H "Authorization: Bearer fh_live_xxx"

#How do tunnels like ngrok fail AI agents?

Tunnels like ngrok create a synchronous bridge between the public internet and your local machine. For this to work, your local process must be online and listening at the exact moment the webhook hits. If your agent is busy, spinning up, or momentarily offline, the webhook is lost (or requires a complex retry strategy from the provider). This synchronous requirement is fundamentally incompatible with how modern AI agents work—they're ephemeral, stateless, and often running in bursts rather than continuously.

#What are the practical problems with ngrok for development?

Beyond the architectural mismatch, ngrok introduces daily friction: (1) URLs change on restart (free tier), requiring you to update webhook configs in Stripe/GitHub dashboards constantly, (2) Rate limits kick in during testing, blocking legitimate webhooks, (3) Connection drops require manual restart and reconfiguration, (4) Team collaboration is difficult—each developer needs their own tunnel and webhook endpoints, (5) No event history—if you miss a webhook, it's gone forever.

1. Start ngrok tunnel: ngrok http 3000
2. Copy new URL: https://abc123.ngrok-free.app
3. Update Stripe dashboard webhook URL
4. Restart local server → ngrok dies
5. Repeat steps 1-3 (URL changed again)
6. Miss webhook during restart → lost forever
7. Hit rate limit → blocked for testing

#Why is a 'Mailbox' better than a 'Tunnel'?

FetchHook acts as a persistent mailbox (or stash). When Stripe or GitHub sends a webhook, FetchHook accepts it instantly and stores it in an encrypted buffer for 24 hours. Your agent can then 'pull' that data whenever it is ready—10 seconds later, 10 minutes later, or after restarting from a crash. The fundamental shift: webhooks become asynchronous messages in a queue, not synchronous HTTP calls requiring immediate response.

• Persistence: Events wait for you; you don't wait for events. 24-hour buffer means zero data loss.
• Security: Zero open ports. No exposure to your local network. All traffic is outbound-only.
• Atomicity: Fetch an event, process it, and it's marked as consumed automatically.
• Static URLs: Set once in provider dashboards, never change again.
• Team-friendly: Multiple developers pull from the same mailbox with different API keys.
• Event history: Replay events during debugging by re-pulling unconsumed messages.

#How does setup complexity compare?

Ngrok Setup:
1. Install ngrok CLI
2. Create ngrok account
3. Start tunnel: ngrok http 3000
4. Copy dynamic URL: https://abc123.ngrok-free.app
5. Configure webhook in provider dashboard
6. Restart server → Repeat steps 3-5
7. Build Express/Flask webhook receiver
8. Add signature verification middleware
9. Handle errors, retries, timeouts

FetchHook Setup:
1. Get your static URL: https://api.fetchhook.app/in/stash_abc123
2. Configure once in provider dashboard
3. Pull events when ready:
   curl https://api.fetchhook.app/api/v1/stash_abc123 \
     -H "Authorization: Bearer fh_live_xxx"

Result: 30 seconds vs 30 minutes

#How do I migrate from ngrok to FetchHook?

Migration is straightforward. Instead of building a webhook receiver endpoint, you build a polling loop or cron job. Replace your Express/Flask webhook handler with a simple fetch call to FetchHook's API. Remove ngrok from your startup scripts. Update your provider's webhook URL to your static FetchHook ingress URL. That's it—no more tunnels, no more dynamic URLs, no more infrastructure.

// OLD: ngrok + Express server (must stay online)
const express = require('express');
const app = express();

app.post('/webhooks/stripe', async (req, res) => {
  // Must respond in <10 seconds or timeout
  const event = req.body;
  await processStripeEvent(event);
  res.status(200).send('OK');
});

app.listen(3000);
// Problem: Server must be running 24/7
// Problem: ngrok URL changes on restart

// NEW: FetchHook pull (no server needed)
const axios = require('axios');

async function processWebhooks() {
  // Pull events whenever ready
  const response = await axios.get(
    'https://api.fetchhook.app/api/v1/stash_stripe',
    { headers: { Authorization: 'Bearer fh_live_xxx' } }
  );

  for (const event of response.data.events) {
    await processStripeEvent(event.payload);
  }
}

// Run via cron every 5 minutes, or on-demand
processWebhooks();
// Benefit: No server needed
// Benefit: URL never changes
// Benefit: Process at your own pace

#When should I still use ngrok?

Use ngrok (or similar tunnels) when: (1) You're testing a full web application with user-facing UI that needs to be publicly accessible, (2) You need to demo something to a client with real-time interaction, (3) You're debugging OAuth flows that require callback URLs, (4) You absolutely need sub-second webhook latency (though FetchHook's buffer adds <100ms). For webhook-driven automation, AI agents, background jobs, and serverless workflows, FetchHook's mailbox model is almost always the better choice.

#What about cost?

Ngrok free tier has dynamic URLs and rate limits. The paid tier ($8-20/month per developer) provides static URLs. FetchHook's free tier includes static URLs, 24-hour persistence, and signature verification. For teams, the cost difference compounds: with ngrok, each developer needs their own tunnel and webhook endpoints. With FetchHook, the entire team pulls from shared mailboxes using scoped API keys. No per-seat pricing, no tunnel management overhead.