Decoy

Product Introduction

1. Definition: Decoy is a native macOS mock server application enabling developers to create local mock services for API testing, webhook simulation, and webpage mocking without external dependencies.
2. Core Value Proposition: It eliminates the complexity of Docker, cloud tunnels, and Electron apps, providing a lightweight (10MB), instant-start solution for testing API failures, redirects, timeouts, and web scraping in isolated local environments.

Main Features

1. Endpoint Configuration: Define HTTP methods (GET, POST, etc.) and path pairs (e.g., /users/:id), grouped into projects with custom subdomains (e.g., api.decoy.my). Uses parameterized paths for dynamic routing.
2. Real-Time Request Monitoring: View incoming requests with headers, body (auto-formatted JSON), source IP, and timestamps. All requests are persisted to SQLite immediately, ensuring zero data loss.
3. Dynamic Response Mocking: Craft responses with 7 body types (JSON, HTML, XML, File, etc.), custom status codes (including redirects: 301, 302), headers, and simulated latency. Changes apply on the next request.
4. CORS & Browser Support: Automatic CORS handling allows seamless browser-based testing. Serve full HTML webpages for scraping/AI agent testing without rate limits.
5. Native Performance: Built with SwiftUI and Network.framework, launching instantly with minimal memory usage. No background processes or config files required.

Problems Solved

1. Pain Point: Overreliance on Docker containers, cloud tunnels (ngrok), and heavy Electron apps for mock testing, leading to slow iteration and bloated systems.
2. Target Audience: macOS developers testing webhooks/APIs, QA engineers simulating failures, data engineers validating scrapers/AI agents, and indie hackers prototyping integrations.
3. Use Cases:
   • Test webhook payloads from production apps locally.
   • Validate API wrapper error handling (e.g., 5xx responses).
   • Mock third-party services (Stripe, Slack) during development.
   • Serve dummy HTML pages to train web scrapers without IP blocks.

Unique Advantages

1. Differentiation: Unlike Docker-based tools (Postman, WireMock) or Electron apps, Decoy offers a truly native macOS experience with zero setup, instant startup, and 10MB footprint. Outperforms cloud solutions by keeping data local.
2. Key Innovation: SQLite persistence ensures request history survives app restarts. Parameterized paths and response snapshots enable complex testing workflows without code.

Frequently Asked Questions (FAQ)

1. Does Decoy require Docker or cloud dependencies?
   No. Decoy is a standalone native macOS app requiring no Docker, cloud tunnels, or external services.
2. Can I test webhooks locally with Decoy?
   Yes. Point external services to decoy.my:8998 (or custom domains like lvh.me) to capture and mock webhook requests locally.
3. How does Decoy handle security and privacy?
   All data stays on-device via local SQLite storage. No tracking, telemetry, or cloud sync.
4. What macOS versions are supported?
   Decoy requires macOS 14 Sonoma or later, leveraging modern SwiftUI and Network.framework APIs.
5. Can I mock binary file responses (e.g., images/PDFs)?
   Yes. Use the File body type to serve any file from disk. Binary request bodies display as hex dumps.