Build a Webhook Inbox in 30 Seconds — Free HTTP Endpoint for AI Agents

Every developer has been there: you're building an integration, and you need a real HTTP endpoint to receive a webhook — but you're on a laptop behind NAT, working in a sandboxed AI environment, or stuck in a CI runner with no public URL.

You could reach for webhook.site or ngrok. But those are separate accounts, browser tabs, or daemons to babysit. What if you could get a disposable webhook inbox URL with a single API call — from curl, a Python script, or even your AI agent's chat interface?

That's what the Agent Media Tools webhook inbox gives you. No signup. No server. One request, and you have a live HTTP endpoint that collects POSTs for you.

What Is a Webhook Inbox?

A webhook inbox is a temporary HTTP endpoint that accepts POST requests and stores them until you poll them. Think of it as a mailbox for machine-to-machine messages:

• Your CI pipeline sends a "deploy finished" POST to your inbox.
• Your AI agent's cron job sends a "data scraped" POST.
• Your monitoring service sends an alert POST.
• Your n8n/Prefect/Temporal workflow sends a "step completed" POST.

Later — from a different machine, a different session, or a different agent — you poll the inbox and get every message that arrived.

Creating a Webhook Inbox

Hit the /api/webhook/inbox endpoint with a friendly name. That's it.

curl -X POST https://agentmediatools.com/api/webhook/inbox \
  -H "Content-Type: application/json" \
  -d '{"name": "deploy-alerts"}'

{
  "name": "deploy-alerts",
  "inbox_url": "https://agentmediatools.com/api/webhook/inbox/deploy-alerts",
  "token": "mt_web_in_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
  "created_at": "2026-07-19T12:00:00Z",
  "message_count": 0
}

The inbox_url is your public endpoint — give this to any service that needs to send you webhooks. The token is how you'll read messages later (keep it secret).

Sending Messages to Your Inbox

Any external service can POST to your inbox URL. No auth required on the sender side — that's intentional. Inboxes accept anonymous POSTs so GitHub, Stripe, Slack, cron jobs, and dumb shell scripts can all deliver to them.

Here's a GitHub Actions workflow sending a deploy notification:

jobs:
  deploy:
    steps:
      - run: echo "Deploying..."
      - name: Notify inbox
        run: |
          curl -X POST https://agentmediatools.com/api/webhook/inbox/deploy-alerts \
            -H "Content-Type: application/json" \
            -d '{"event":"deploy","status":"success","commit":"abc123"}'

Every POST gets a timestamp and a unique ID. The inbox stores up to 100 messages before rotating oldest-first.

Polling Your Inbox (Reading Messages)

Now the magic part: from anywhere — a different laptop, an AI agent running in the cloud, a mobile phone terminal — you poll with your token and read everything.

curl "https://agentmediatools.com/api/webhook/inbox/deploy-alerts?token=mt_web_in_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"

{
  "name": "deploy-alerts",
  "messages": [
    {
      "id": "msg_001",
      "timestamp": "2026-07-19T12:05:00Z",
      "headers": {"content-type": "application/json"},
      "body": {"event": "deploy", "status": "success", "commit": "abc123"}
    }
  ],
  "pending": 1
}

Messages are consumed on read by default — once you poll, they're removed from the queue. This prevents duplicate processing. You can also pass ?peek=true to read without consuming, useful for debugging.

Python Example: Poll-and-Process Loop

Here's a minimal Python script that polls your inbox every 30 seconds and processes messages:

import requests, time, json

INBOX = "deploy-alerts"
TOKEN = "mt_web_in_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"

while True:
    r = requests.get(
        f"https://agentmediatools.com/api/webhook/inbox/{INBOX}",
        params={"token": TOKEN}
    )
    for msg in r.json().get("messages", []):
        body = msg.get("body", {})
        print(f"[{msg['id']}] {body.get('event')} — {body.get('status')}")
        # Handle the webhook
    time.sleep(30)

Using the Inbox with n8n / Make / Zapier

Webhook inboxes are perfect for low-code platforms:

1. n8n: Use a Webhook node pointing to https://agentmediatools.com/api/webhook/inbox/your-name as the POST target. Then use an HTTP Request node with your token to poll results into any downstream workflow.
2. Make (Integromat): Create a webhook module with your inbox URL as the endpoint. Use the "Watch Webhook" trigger pattern.
3. Zapier: Use "Webhooks by Zapier" → "Catch Hook" with your inbox URL.

Why Not Just Use a Local Server?

Because you can't always run one:

• AI agent sandboxes — Claude, ChatGPT, and Hermes run in sandboxed environments with no inbound networking. They can POST out, but they can't listen for incoming connections. A webhook inbox flips this: your agent creates the inbox, an external service POSTs to it, and the agent polls the results later.
• CI/CD runners — GitHub Actions, GitLab CI, and Jenkins runners are ephemeral. By the time a webhook arrives, the runner is gone. With an inbox, your CI POSTs its status before it dies, and you check the results from wherever you want.
• Multi-step workflows — Step A kicks off a long-running job, Step B picks up the result. An inbox decouples the two perfectly.

Use Cases for AI Agents

This pattern is especially useful when building autonomous agent workflows:

• Research agent → fires off a web scraping job → scraped data POSTs to inbox → agent polls and summarizes.
• Deployment agent → triggers deploy → CI/CD POSTs result to inbox → agent detects failure and rolls back.
• Monitoring agent → sleeps → alert webhooks arrive in inbox → agent wakes, polls, and responds.
• Coordinator agent → spawns sub-agents → each sub-agent POSTs its result to a shared inbox → coordinator collects all results and produces a final report.

If your agent has the MCP tools active, it can create inboxes and poll them directly from conversation. On Hermes, the create_webhook_inbox and mailbox_poll MCP tools expose the same functionality.

Limits & Notes

• Inboxes expire after 24 hours of inactivity. Active inboxes (with recent POSTs or polls) stay alive.
• Each inbox holds up to 100 messages. Oldest messages are dropped first when the limit is exceeded.
• Message bodies are limited to 64 KB per POST.
• No authentication required to POST — anyone who knows your inbox URL can send to it. Treat it like an unlisted webhook endpoint.
• The token is required to read or delete messages — keep it private.

Try It Now

You don't need an account. You don't need an API key. Open a terminal and run:

curl -s -X POST https://agentmediatools.com/api/webhook/inbox \
  -H "Content-Type: application/json" \
  -d '{"name":"test-'$(date +%s)'"}'

You'll get a live inbox URL in under a second. POST some JSON to it, then poll it back. That's the whole loop — and it works from anywhere.

Need more control? The same inbox system is available through the Agent Hub with MCP support, message TTLs, and webhook-out delivery to Discord, Telegram, or email.