simceptor-cli

Route webhook events from the cloud directly to your localhost — no Ngrok, no tunnel, no port forwarding.

🚀 Quick Start (30 seconds)

Step 1 — Create a free account at simceptor.com

Or run this to open the registration page automatically:

npx simceptor-cli init

Step 2 — In the dashboard, go to Developer Keys and generate a token with relay scope.

Step 3 — Start listening:

npx simceptor-cli listen --token <YOUR_TOKEN>

That's it. Webhooks sent to your Simceptor endpoints will now be forwarded to http://localhost:3000.

🤔 What is Simceptor?

Simceptor is an advanced Mock API & Simulator Platform. It lets you:

• 🎯 Define Conditional Logic — IF-THEN response rules based on body, headers, query params, or path
• ⏱️ Simulate Latency — per-endpoint or per-rule network delay simulation
• 🔄 Inject Dynamic Data — template engines and Faker variables in responses
• 🤖 Work alongside AI Agents — built-in MCP (Model Context Protocol) Server for Claude, Cursor, etc.
• 🔌 Relay Webhooks locally — using this CLI tool

⚡ The Problem This Solves

Testing webhook integrations locally is painful. Cloud providers (Stripe, Twilio, GitHub, etc.) cannot send HTTP callbacks to http://localhost because your machine is behind a NAT/firewall.

simceptor-cli solves this by opening a persistent WebSocket connection to your Simceptor project. Incoming webhooks are tunneled through that connection and forwarded to your local server — without exposing any port to the internet.

📖 Usage

# Open registration page in browser
simceptor init

# Start relaying webhooks to localhost:3000 (default)
simceptor listen --token <TOKEN>

# Relay to a different local port
simceptor listen --token <TOKEN> --to http://localhost:8080

# Self-hosted Simceptor instance
simceptor listen --token <TOKEN> --server wss://your-own-host.com

Options for listen

| Flag | Default | Description | |---|---|---| | -t, --token (required) | — | Personal Access Token from Developer Keys | | -o, --to | http://localhost:3000 | Local server URL to forward webhooks to | | -s, --server | wss://simceptor.com | Simceptor server (override for self-hosted) |

🔒 Security

• Connections are guarded by scoped Personal Access Tokens (PAT)
• Generate tokens with only the relay scope — they cannot modify your mocks or projects
• Always uses wss:// (encrypted) on simceptor.com

📄 License

MIT License. Copyright (c) 2026.